feat: add first person view (FPV) functionality and HUD (#9)

* feat: add first person view (FPV) functionality and HUD

- Updated FlightCard component to include FPV toggle button and state management.
- Introduced FpvHud component for displaying flight data in FPV mode.
- Enhanced useFlights hook to support FPV bounding box logic for fetching flights.
- Added keyboard shortcuts for toggling FPV mode.
- Updated settings to include FPV-related configurations (pitch, chase distance).
- Implemented major airports caching for improved performance.
- Added fetchFlightByIcao24 function for single aircraft state retrieval.

* Refactor CameraController and ControlPanel components; enhance flight search functionality

- Simplified CameraController by removing unused refs and effects, and centralized map interaction management.
- Updated ControlPanel to support flight lookup with new props and integrated flight search results.
- Enhanced SearchContent to include flight matching logic and improved user feedback for flight searches.
- Introduced caching for flight callsign lookups in OpenSky API integration to optimize performance.
- Removed unnecessary settings related to FPV pitch and free camera mode from use-settings hook.

* feat: enhance FPV functionality and improve flight data handling

- Added `projectLngLatElevationPixelDelta` function to calculate pixel deltas based on longitude, latitude, and elevation.
- Updated `CameraController` to utilize new FPV parameters and improve camera behavior during flight.
- Enhanced flight data handling in `FlightLayers` to ensure proper tracking and display of flight information.
- Improved UI components for better user experience, including adjustments to the FPV HUD and flight card.
- Added error handling for image loading in the control panel.
- Refactored altitude and speed calculations to ensure they handle non-finite values gracefully.
- Adjusted map attribution behavior for better responsiveness on different screen sizes.

.gitignore

@@ -44,3 +44,4 @@ next-env.d.ts
 
 # local documentation
 docs.txt
+ROADMAP.local.md

src/components/flight-tracker.tsx

@@ -8,13 +8,14 @@ import {
   useRef,
   useSyncExternalStore,
 } from "react";
-import { motion } from "motion/react";
+import { motion, AnimatePresence } from "motion/react";
 import { ErrorBoundary } from "@/components/error-boundary";
-import { Map } from "@/components/map/map";
+import { Map as MapView } from "@/components/map/map";
 import { CameraController } from "@/components/map/camera-controller";
 import { AirportLayer } from "@/components/map/airport-layer";
 import { FlightLayers } from "@/components/map/flight-layers";
 import { FlightCard } from "@/components/ui/flight-card";
+import { FpvHud } from "@/components/ui/fpv-hud";
 import { KeyboardShortcutsHelp } from "@/components/ui/keyboard-shortcuts-help";
 import { ControlPanel } from "@/components/ui/control-panel";
 import { AltitudeLegend } from "@/components/ui/altitude-legend";
@@ -28,7 +29,12 @@ import { useTrailHistory } from "@/hooks/use-trail-history";
 import { MAP_STYLES, DEFAULT_STYLE, type MapStyle } from "@/lib/map-styles";
 import { CITIES, type City } from "@/lib/cities";
 import { AIRPORTS, findByIata, airportToCity } from "@/lib/airports";
-import type { FlightState } from "@/lib/opensky";
+import {
+  fetchFlightByIcao24,
+  fetchFlightByCallsign,
+  type FlightState,
+} from "@/lib/opensky";
+import { formatCallsign } from "@/lib/flight-utils";
 import type { PickingInfo } from "@deck.gl/core";
 import { Github, Star, Keyboard } from "lucide-react";
 
@@ -65,6 +71,7 @@ const HIGH_TRAFFIC_IATA_SET = new Set<string>(HIGH_TRAFFIC_IATA);
 const HIGH_TRAFFIC_AIRPORTS = AIRPORTS.filter((airport) =>
   HIGH_TRAFFIC_IATA_SET.has(airport.iata.toUpperCase()),
 );
+const ICAO24_REGEX = /^[0-9a-f]{6}$/i;
 
 const subscribeNoop = () => () => {};
 
@@ -107,12 +114,46 @@ function syncCityToUrl(city: City): void {
   try {
     const url = new URL(window.location.href);
     url.searchParams.set("city", city.iata);
+    url.searchParams.delete("from");
+    url.searchParams.delete("to");
+    url.searchParams.delete("fpv");
     window.history.replaceState(null, "", url.toString());
   } catch {
     /* ignore */
   }
 }
 
+function syncFpvToUrl(icao24: string | null, activeCity?: City): void {
+  if (typeof window === "undefined") return;
+  try {
+    const url = new URL(window.location.href);
+    if (icao24) {
+      url.searchParams.set("fpv", icao24);
+      url.searchParams.delete("city");
+      url.searchParams.delete("from");
+      url.searchParams.delete("to");
+    } else {
+      url.searchParams.delete("fpv");
+      if (activeCity) {
+        url.searchParams.set("city", activeCity.iata);
+      }
+    }
+    window.history.replaceState(null, "", url.toString());
+  } catch {
+    /* ignore */
+  }
+}
+
+function resolveInitialFpv(): string | null {
+  try {
+    const params = new URLSearchParams(window.location.search);
+    const raw = params.get("fpv")?.trim().toLowerCase();
+    return raw && /^[0-9a-f]{6}$/.test(raw) ? raw : null;
+  } catch {
+    return null;
+  }
+}
+
 function loadMapStyle(): MapStyle {
   try {
     const id = localStorage.getItem(STYLE_STORAGE_KEY);
@@ -157,6 +198,19 @@ function pickRandomAirportCity(excludeIata?: string): City {
   return airportToCity(randomAirport);
 }
 
+function cityFromFlight(flight: FlightState): City | null {
+  if (flight.longitude == null || flight.latitude == null) return null;
+  const code = flight.icao24.toUpperCase();
+  return {
+    id: `trk-${flight.icao24}`,
+    name: `Flight ${code}`,
+    country: flight.originCountry || "Unknown",
+    iata: code.slice(0, 3),
+    coordinates: [flight.longitude, flight.latitude],
+    radius: 2,
+  };
+}
+
 function FlightTrackerInner() {
   const hydratedCity = useSyncExternalStore(
     subscribeNoop,
@@ -174,6 +228,22 @@ function FlightTrackerInner() {
   const [selectedIcao24, setSelectedIcao24] = useState<string | null>(null);
   const [showHelp, setShowHelp] = useState(false);
   const [repoStars, setRepoStars] = useState<number | null>(null);
+  const [followIcao24, setFollowIcao24] = useState<string | null>(null);
+  const [fpvIcao24, setFpvIcao24] = useState<string | null>(null);
+
+  const pendingFpvRef = useRef<string | null>(resolveInitialFpv());
+
+  const fpvPositionRef = useRef<{
+    lng: number;
+    lat: number;
+    alt: number;
+    track: number;
+  } | null>(null);
+
+  const [fpvSeedCenter, setFpvSeedCenter] = useState<{
+    lng: number;
+    lat: number;
+  } | null>(null);
 
   const activeCity = cityOverride ?? hydratedCity;
   const mapStyle = styleOverride ?? hydratedStyle;
@@ -182,6 +252,8 @@ function FlightTrackerInner() {
   const setActiveCity = useCallback((city: City) => {
     setCityOverride(city);
     setSelectedIcao24(null);
+    setFpvIcao24(null);
+    setFollowIcao24(null);
     syncCityToUrl(city);
   }, []);
 
@@ -189,24 +261,157 @@ function FlightTrackerInner() {
     setStyleOverride(style);
     saveMapStyle(style);
   }, []);
-  const { flights, loading, rateLimited, retryIn } = useFlights(activeCity);
+  const { flights, loading, rateLimited, retryIn } = useFlights(
-  const trails = useTrailHistory(flights);
+    activeCity,
+    fpvIcao24,
+    fpvSeedCenter,
+  );
+
+  const displayFlights = flights;
+  const displayTrails = useTrailHistory(displayFlights);
 
   const selectedFlight = useMemo(() => {
     if (!selectedIcao24) return null;
-    return flights.find((f) => f.icao24 === selectedIcao24) ?? null;
+    return (
-  }, [selectedIcao24, flights]);
+      displayFlights.find((f) => f.icao24.toLowerCase() === selectedIcao24) ??
+      null
+    );
+  }, [selectedIcao24, displayFlights]);
+
+  const followFlight = useMemo(() => {
+    if (!followIcao24) return null;
+    return (
+      displayFlights.find((f) => f.icao24.toLowerCase() === followIcao24) ??
+      null
+    );
+  }, [followIcao24, displayFlights]);
+
+  const fpvFlight = useMemo(() => {
+    if (!fpvIcao24) return null;
+    return (
+      displayFlights.find((f) => f.icao24.toLowerCase() === fpvIcao24) ?? null
+    );
+  }, [fpvIcao24, displayFlights]);
 
-  const lastKnownFlightRef = useRef<FlightState | null>(null);
   useEffect(() => {
-    if (selectedFlight) lastKnownFlightRef.current = selectedFlight;
+    syncFpvToUrl(fpvIcao24, activeCity);
-    if (!selectedIcao24) lastKnownFlightRef.current = null;
+  }, [fpvIcao24, activeCity]);
-  }, [selectedFlight, selectedIcao24]);
 
-  // Safe: ref only changes in the effect above, which runs after state-driven re-renders.
+  const fpvLookupDoneRef = useRef(false);
-  const displayFlight =
+  useEffect(() => {
-    // eslint-disable-next-line react-hooks/refs
+    const pending = pendingFpvRef.current;
-    selectedFlight ?? (selectedIcao24 ? lastKnownFlightRef.current : null);
+    if (!pending || fpvIcao24) return;
+
+    const match = displayFlights.find(
+      (f) => f.icao24.toLowerCase() === pending,
+    );
+    if (match && match.longitude != null && match.latitude != null) {
+      if (match.onGround) {
+        pendingFpvRef.current = null;
+        syncFpvToUrl(null, activeCity);
+        setSelectedIcao24(match.icao24);
+        return;
+      }
+      pendingFpvRef.current = null;
+      fpvLookupDoneRef.current = false;
+      setFpvSeedCenter({ lng: match.longitude, lat: match.latitude });
+      setFpvIcao24(pending);
+      setFollowIcao24(null);
+      return;
+    }
+
+    if (!fpvLookupDoneRef.current && displayFlights.length > 0) {
+      fpvLookupDoneRef.current = true;
+      const controller = new AbortController();
+      fetchFlightByIcao24(pending, controller.signal)
+        .then((result) => {
+          if (
+            result.flight &&
+            result.flight.longitude != null &&
+            result.flight.latitude != null &&
+            !result.flight.onGround &&
+            pendingFpvRef.current === pending
+          ) {
+            const focusCity = cityFromFlight(result.flight);
+            if (focusCity) {
+              setCityOverride(focusCity);
+            }
+            setFpvSeedCenter({
+              lng: result.flight.longitude,
+              lat: result.flight.latitude,
+            });
+            pendingFpvRef.current = null;
+            setFpvIcao24(pending);
+            setFollowIcao24(null);
+          } else if (pendingFpvRef.current === pending) {
+            pendingFpvRef.current = null;
+            syncFpvToUrl(null, activeCity);
+            if (result.flight) {
+              setSelectedIcao24(result.flight.icao24);
+            }
+          }
+        })
+        .catch(() => {
+          if (pendingFpvRef.current === pending) {
+            pendingFpvRef.current = null;
+          }
+        });
+      return () => controller.abort();
+    }
+  }, [displayFlights, fpvIcao24, activeCity]);
+
+  const fpvFlightOrCached = fpvFlight;
+
+  const fpvMissCountRef = useRef(0);
+  useEffect(() => {
+    if (!fpvIcao24) {
+      fpvMissCountRef.current = 0;
+      return;
+    }
+
+    if (fpvFlight) {
+      fpvMissCountRef.current = 0;
+      if (fpvFlight.onGround) {
+        const exitIcao = fpvIcao24;
+        const timer = setTimeout(() => {
+          setSelectedIcao24(exitIcao);
+          setFpvIcao24(null);
+        }, 0);
+        return () => clearTimeout(timer);
+      }
+    } else {
+      if (!rateLimited) {
+        fpvMissCountRef.current += 1;
+      }
+      if (fpvMissCountRef.current >= 3) {
+        const exitIcao = fpvIcao24;
+        const timer = setTimeout(() => {
+          setSelectedIcao24(exitIcao);
+          setFpvIcao24(null);
+        }, 0);
+        return () => clearTimeout(timer);
+      }
+    }
+  }, [fpvIcao24, fpvFlight, rateLimited]);
+
+  const followMissCountRef = useRef(0);
+  useEffect(() => {
+    if (!followIcao24) {
+      followMissCountRef.current = 0;
+      return;
+    }
+    if (followFlight) {
+      followMissCountRef.current = 0;
+    } else {
+      followMissCountRef.current += 1;
+      if (followMissCountRef.current >= 3) {
+        const timer = setTimeout(() => setFollowIcao24(null), 0);
+        return () => clearTimeout(timer);
+      }
+    }
+  }, [followIcao24, followFlight]);
+
+  const displayFlight = selectedFlight;
 
   const missingSinceRef = useRef<number | null>(null);
   useEffect(() => {
@@ -218,17 +423,17 @@ function FlightTrackerInner() {
       missingSinceRef.current = null;
       return;
     }
-    // Flight is selected but not in the current flights list.
     const now = Date.now();
     if (missingSinceRef.current == null) {
       missingSinceRef.current = now;
       return;
     }
     if (now - missingSinceRef.current >= 30_000) {
-      setSelectedIcao24(null);
+      const timer = setTimeout(() => setSelectedIcao24(null), 0);
       missingSinceRef.current = null;
+      return () => clearTimeout(timer);
     }
-  }, [selectedIcao24, selectedFlight, flights]);
+  }, [selectedIcao24, selectedFlight, displayFlights]);
 
   useEffect(() => {
     let mounted = true;
@@ -252,19 +457,55 @@ function FlightTrackerInner() {
     };
   }, []);
 
-  const handleClick = useCallback((info: PickingInfo<FlightState> | null) => {
+  const handleClick = useCallback(
-    if (info?.object) {
+    (info: PickingInfo<FlightState> | null) => {
-      setSelectedIcao24((prev) =>
+      if (fpvIcao24) return;
-        prev === info.object!.icao24 ? null : info.object!.icao24,
+      if (info?.object) {
-      );
+        const icao24 = info.object.icao24.toLowerCase();
+        setSelectedIcao24((prev) => (prev === icao24 ? null : icao24));
+      } else {
+        setSelectedIcao24(null);
+      }
+    },
+    [fpvIcao24],
+  );
+
+  const handleDeselectFlight = useCallback(() => {
+    if (fpvIcao24) {
+      setSelectedIcao24(fpvIcao24);
+      setFpvIcao24(null);
     } else {
       setSelectedIcao24(null);
     }
-  }, []);
+  }, [fpvIcao24]);
 
-  const handleDeselectFlight = useCallback(() => {
+  const handleToggleFpv = useCallback(
-    setSelectedIcao24(null);
+    (icao24: string) => {
-  }, []);
+      const targetIcao24 = icao24.toLowerCase();
+      const flight =
+        displayFlights.find((f) => f.icao24.toLowerCase() === targetIcao24) ??
+        flights.find((f) => f.icao24.toLowerCase() === targetIcao24);
+      if (!flight) return;
+      if (flight.longitude == null || flight.latitude == null) return;
+      if (flight.onGround) return;
+      setFpvSeedCenter({ lng: flight.longitude, lat: flight.latitude });
+      setFpvIcao24((prev) => {
+        if (prev === targetIcao24) {
+          setFpvSeedCenter(null);
+          setSelectedIcao24(targetIcao24);
+          return null;
+        }
+        return targetIcao24;
+      });
+      setFollowIcao24(null);
+    },
+    [displayFlights, flights],
+  );
+
+  const handleExitFpv = useCallback(() => {
+    setSelectedIcao24(fpvIcao24);
+    setFpvIcao24(null);
+  }, [fpvIcao24]);
 
   const handleNorthUp = useCallback(() => {
     window.dispatchEvent(new CustomEvent("aeris:north-up"));
@@ -295,6 +536,79 @@ function FlightTrackerInner() {
     setShowHelp((prev) => !prev);
   }, []);
 
+  const handleToggleFpvKey = useCallback(() => {
+    if (fpvIcao24) {
+      setSelectedIcao24(fpvIcao24);
+      setFpvIcao24(null);
+    } else if (selectedIcao24) {
+      handleToggleFpv(selectedIcao24);
+    }
+  }, [fpvIcao24, selectedIcao24, handleToggleFpv]);
+
+  const handleLookupFlight = useCallback(
+    async (rawQuery: string, enterFpv = false): Promise<boolean> => {
+      const compactQuery = rawQuery.trim().toLowerCase().replace(/\s+/g, "");
+      if (!compactQuery) return false;
+
+      const localMatch =
+        displayFlights.find((f) => f.icao24.toLowerCase() === compactQuery) ??
+        displayFlights.find((f) =>
+          formatCallsign(f.callsign)
+            .toLowerCase()
+            .replace(/\s+/g, "")
+            .includes(compactQuery),
+        ) ??
+        null;
+
+      if (localMatch) {
+        setSelectedIcao24(localMatch.icao24);
+        setFollowIcao24(null);
+        if (
+          enterFpv &&
+          !localMatch.onGround &&
+          localMatch.longitude != null &&
+          localMatch.latitude != null
+        ) {
+          setFpvSeedCenter({
+            lng: localMatch.longitude,
+            lat: localMatch.latitude,
+          });
+          setFpvIcao24(localMatch.icao24);
+        }
+        return true;
+      }
+
+      const result = ICAO24_REGEX.test(compactQuery)
+        ? await fetchFlightByIcao24(compactQuery)
+        : await fetchFlightByCallsign(compactQuery);
+
+      if (!result.flight) return false;
+
+      const focusCity = cityFromFlight(result.flight);
+      if (focusCity) {
+        setCityOverride(focusCity);
+        syncCityToUrl(focusCity);
+      }
+
+      setSelectedIcao24(result.flight.icao24);
+      setFollowIcao24(null);
+      if (
+        enterFpv &&
+        !result.flight.onGround &&
+        result.flight.longitude != null &&
+        result.flight.latitude != null
+      ) {
+        setFpvSeedCenter({
+          lng: result.flight.longitude,
+          lat: result.flight.latitude,
+        });
+        setFpvIcao24(result.flight.icao24);
+      }
+      return true;
+    },
+    [displayFlights],
+  );
+
   useKeyboardShortcuts({
     onNorthUp: handleNorthUp,
     onResetView: handleResetView,
@@ -302,126 +616,163 @@ function FlightTrackerInner() {
     onOpenSearch: handleOpenSearch,
     onToggleHelp: handleToggleHelp,
     onDeselect: handleDeselectFlight,
+    onToggleFpv: handleToggleFpvKey,
+    isFpv: fpvIcao24 !== null,
   });
 
   return (
     <main className="relative h-dvh w-screen overflow-hidden bg-black">
-      <Map mapStyle={mapStyle.style} isDark={mapStyle.dark}>
+      <MapView mapStyle={mapStyle.style} isDark={mapStyle.dark}>
-        <CameraController city={activeCity} />
+        <CameraController
+          city={activeCity}
+          followFlight={followFlight}
+          fpvFlight={fpvFlightOrCached}
+          fpvPositionRef={fpvPositionRef}
+        />
         <AirportLayer
           activeCity={activeCity}
           onSelectAirport={setActiveCity}
           isDark={mapStyle.dark}
         />
         <FlightLayers
-          flights={flights}
+          flights={displayFlights}
-          trails={trails}
+          trails={displayTrails}
           onClick={handleClick}
-          selectedIcao24={selectedIcao24}
+          selectedIcao24={fpvIcao24 ?? selectedIcao24}
           showTrails={settings.showTrails}
           trailThickness={settings.trailThickness}
           trailDistance={settings.trailDistance}
           showShadows={settings.showShadows}
           showAltitudeColors={settings.showAltitudeColors}
+          fpvIcao24={fpvIcao24}
+          fpvPositionRef={fpvPositionRef}
         />
-      </Map>
+      </MapView>
 
       <div
         data-map-theme={mapStyle.dark ? "dark" : "light"}
         className="pointer-events-none absolute inset-0 z-10"
       >
-        <div className="pointer-events-auto absolute left-3 top-3 flex items-center gap-3 sm:left-4 sm:top-4">
+        {!fpvIcao24 && (
-          <Brand isDark={mapStyle.dark} />
+          <div className="pointer-events-auto absolute left-3 top-3 flex items-center gap-3 sm:left-4 sm:top-4">
-        </div>
+            <Brand isDark={mapStyle.dark} />
+          </div>
+        )}
 
-        <div className="pointer-events-auto absolute left-3 top-14 sm:left-4 sm:top-16">
+        {!fpvIcao24 && (
-          <FlightCard flight={displayFlight} onClose={handleDeselectFlight} />
+          <div className="pointer-events-auto absolute left-3 top-14 sm:left-4 sm:top-16">
-        </div>
+            <FlightCard
+              flight={displayFlight}
+              onClose={handleDeselectFlight}
+              onToggleFpv={handleToggleFpv}
+              isFpvActive={
+                fpvIcao24 !== null && fpvIcao24 === displayFlight?.icao24
+              }
+            />
+          </div>
+        )}
 
-        <div className="pointer-events-auto absolute right-3 top-3 flex items-center gap-1.5 sm:right-4 sm:top-4 sm:gap-2">
+        {!fpvIcao24 && (
-          <motion.button
+          <div className="pointer-events-auto absolute right-3 top-3 flex items-center gap-1.5 sm:right-4 sm:top-4 sm:gap-2">
-            onClick={handleToggleHelp}
+            <motion.button
-            className="hidden h-9 w-9 items-center justify-center rounded-xl backdrop-blur-2xl transition-colors sm:flex"
+              onClick={handleToggleHelp}
-            style={{
+              className="hidden h-9 w-9 items-center justify-center rounded-xl backdrop-blur-2xl transition-colors sm:flex"
-              borderWidth: 1,
+              style={{
-              borderColor: "rgb(var(--ui-fg) / 0.06)",
+                borderWidth: 1,
-              backgroundColor: "rgb(var(--ui-fg) / 0.03)",
+                borderColor: "rgb(var(--ui-fg) / 0.06)",
-              color: "rgb(var(--ui-fg) / 0.5)",
+                backgroundColor: "rgb(var(--ui-fg) / 0.03)",
-            }}
+                color: "rgb(var(--ui-fg) / 0.5)",
-            whileHover={{ scale: 1.05 }}
+              }}
-            whileTap={{ scale: 0.95 }}
+              whileHover={{ scale: 1.05 }}
-            aria-label="Keyboard shortcuts"
+              whileTap={{ scale: 0.95 }}
-            title="Keyboard shortcuts (?)"
+              aria-label="Keyboard shortcuts"
-          >
+              title="Keyboard shortcuts (?)"
-            <Keyboard className="h-4 w-4" />
+            >
-          </motion.button>
+              <Keyboard className="h-4 w-4" />
-          <a
+            </motion.button>
-            href={GITHUB_REPO_URL}
+            <a
-            target="_blank"
+              href={GITHUB_REPO_URL}
-            rel="noreferrer"
+              target="_blank"
-            aria-label="Open GitHub repository"
+              rel="noreferrer"
-            className="relative inline-flex h-9 w-9 items-center justify-center rounded-xl backdrop-blur-2xl transition-colors"
+              aria-label="Open GitHub repository"
-            style={{
+              className="relative inline-flex h-9 w-9 items-center justify-center rounded-xl backdrop-blur-2xl transition-colors"
-              borderWidth: 1,
+              style={{
-              borderColor: "rgb(var(--ui-fg) / 0.06)",
+                borderWidth: 1,
-              backgroundColor: "rgb(var(--ui-fg) / 0.03)",
+                borderColor: "rgb(var(--ui-fg) / 0.06)",
-              color: "rgb(var(--ui-fg) / 0.5)",
+                backgroundColor: "rgb(var(--ui-fg) / 0.03)",
-            }}
+                color: "rgb(var(--ui-fg) / 0.5)",
-            title={
+              }}
-              repoStars != null
+              title={
-                ? `GitHub · ${formatStarCount(repoStars)} stars`
+                repoStars != null
-                : "Open GitHub repository"
+                  ? `GitHub · ${formatStarCount(repoStars)} stars`
-            }
+                  : "Open GitHub repository"
-          >
+              }
-            <Github className="h-4 w-4" />
+            >
-            {repoStars != null && (
+              <Github className="h-4 w-4" />
-              <span
+              {repoStars != null && (
-                className="pointer-events-none absolute -bottom-1 -right-1 rounded-full px-1.5 py-0.5 text-[9px] font-semibold tabular-nums"
+                <span
-                style={{
+                  className="pointer-events-none absolute -bottom-1 -right-1 rounded-full px-1.5 py-0.5 text-[9px] font-semibold tabular-nums"
-                  backgroundColor: "rgb(var(--ui-bg) / 0.95)",
+                  style={{
-                  border: "1px solid rgb(var(--ui-fg) / 0.1)",
+                    backgroundColor: "rgb(var(--ui-bg) / 0.95)",
-                  color: "rgb(var(--ui-fg) / 0.55)",
+                    border: "1px solid rgb(var(--ui-fg) / 0.1)",
-                }}
+                    color: "rgb(var(--ui-fg) / 0.55)",
-              >
+                  }}
-                <span className="flex items-center gap-0.5">
+                >
-                  <Star className="h-2 w-2" />
+                  <span className="flex items-center gap-0.5">
-                  {formatStarCount(repoStars)}
+                    <Star className="h-2 w-2" />
+                    {formatStarCount(repoStars)}
+                  </span>
                 </span>
-              </span>
+              )}
-            )}
+            </a>
-          </a>
+            <ControlPanel
-          <ControlPanel
+              activeCity={activeCity}
-            activeCity={activeCity}
+              onSelectCity={setActiveCity}
-            onSelectCity={setActiveCity}
+              activeStyle={mapStyle}
-            activeStyle={mapStyle}
+              onSelectStyle={setMapStyle}
-            onSelectStyle={setMapStyle}
+              flights={displayFlights}
-          />
+              activeFlightIcao24={selectedIcao24}
-        </div>
+              onLookupFlight={handleLookupFlight}
+            />
+          </div>
+        )}
 
-        <div className="pointer-events-auto absolute bottom-[env(safe-area-inset-bottom,0px)] left-3 mb-3 sm:bottom-4 sm:left-4 sm:mb-0">
+        {!fpvIcao24 && (
-          <StatusBar
+          <div className="pointer-events-auto absolute bottom-[env(safe-area-inset-bottom,0px)] left-3 mb-3 sm:bottom-4 sm:left-4 sm:mb-0">
-            flightCount={flights.length}
+            <StatusBar
-            cityName={activeCity.name}
+              flightCount={flights.length}
-            loading={loading}
+              cityName={activeCity.name}
-            rateLimited={rateLimited}
+              loading={loading}
-            retryIn={retryIn}
+              rateLimited={rateLimited}
-            onNorthUp={handleNorthUp}
+              retryIn={retryIn}
-            onResetView={handleResetView}
+              onNorthUp={handleNorthUp}
-            onRandomAirport={handleRandomAirport}
+              onResetView={handleResetView}
-          />
+              onRandomAirport={handleRandomAirport}
-        </div>
+            />
+          </div>
+        )}
 
-        <div className="pointer-events-auto absolute bottom-[env(safe-area-inset-bottom,0px)] right-3 mb-3 flex flex-col items-end gap-2 sm:bottom-4 sm:right-4 sm:mb-0">
+        {!fpvIcao24 && (
-          <CameraControls />
+          <div className="pointer-events-auto absolute bottom-[env(safe-area-inset-bottom,0px)] right-3 mb-3 flex flex-col items-end gap-2 sm:bottom-4 sm:right-4 sm:mb-0">
-          <AltitudeLegend />
+            <CameraControls />
-          <MapAttribution styleId={mapStyle.id} />
+            <AltitudeLegend />
-        </div>
+            <MapAttribution styleId={mapStyle.id} />
+          </div>
+        )}
       </div>
 
-      <KeyboardShortcutsHelp
+      {!fpvIcao24 && (
-        open={showHelp}
+        <KeyboardShortcutsHelp
-        onClose={() => setShowHelp(false)}
+          open={showHelp}
-      />
+          onClose={() => setShowHelp(false)}
+        />
+      )}
+
+      <AnimatePresence>
+        {fpvIcao24 && fpvFlightOrCached && (
+          <FpvHud flight={fpvFlightOrCached} onExit={handleExitFpv} />
+        )}
+      </AnimatePresence>
     </main>
   );
 }

src/components/map/camera-controller-utils.ts

@@ -0,0 +1,93 @@
+import type maplibregl from "maplibre-gl";
+import { MercatorCoordinate } from "maplibre-gl";
+
+export const FPV_DISTANCE_ZOOM_OFFSET = 1.1;
+
+export function clamp01(value: number): number {
+  return Math.max(0, Math.min(1, value));
+}
+
+export function smoothstep(t: number): number {
+  return t * t * (3 - 2 * t);
+}
+
+export function lerp(from: number, to: number, t: number): number {
+  return from + (to - from) * t;
+}
+
+export function normalizeLng(lng: number): number {
+  return ((lng + 540) % 360) - 180;
+}
+
+export function lerpLng(from: number, to: number, t: number): number {
+  const delta = ((to - from + 540) % 360) - 180;
+  return normalizeLng(from + delta * t);
+}
+
+export function fpvZoomForAltitude(altMeters: number): number {
+  if (!Number.isFinite(altMeters)) return 12;
+  const alt = Math.max(altMeters, 0);
+  if (alt < 50) return 16.2;
+  const zoom = 18.1 - 2.0 * Math.log10(Math.max(alt, 50));
+  return Math.max(10.1, Math.min(16.2, zoom));
+}
+
+export function projectLngLatElevationPixelDelta(
+  map: maplibregl.Map,
+  lng: number,
+  lat: number,
+  elevationMeters: number,
+): { dx: number; dy: number } | null {
+  type Transform3DLike = {
+    _pixelMatrix3D?: unknown;
+    centerPoint?: { x: number; y: number };
+    coordinatePoint: (
+      coord: MercatorCoordinate,
+      elevation: number,
+      pixelMatrix3D: unknown,
+    ) => { x: number; y: number } | null;
+  };
+
+  const tr = (map as unknown as { transform?: Transform3DLike }).transform;
+  if (!tr || typeof tr.coordinatePoint !== "function") return null;
+
+  const pixelMatrix3D = tr._pixelMatrix3D;
+  const centerPoint = tr.centerPoint;
+  if (!pixelMatrix3D || !centerPoint) return null;
+
+  let p: { x: number; y: number } | null = null;
+  try {
+    p = tr.coordinatePoint(
+      MercatorCoordinate.fromLngLat({ lng, lat }),
+      elevationMeters,
+      pixelMatrix3D,
+    );
+  } catch {
+    return null;
+  }
+
+  if (!p || !Number.isFinite(p.x) || !Number.isFinite(p.y)) return null;
+  return { dx: p.x - centerPoint.x, dy: p.y - centerPoint.y };
+}
+
+export function setMapInteractionsEnabled(
+  map: maplibregl.Map,
+  enabled: boolean,
+): void {
+  if (enabled) {
+    map.dragPan.enable();
+    map.dragRotate.enable();
+    map.scrollZoom.enable();
+    map.touchZoomRotate.enable();
+    map.doubleClickZoom.enable();
+    map.keyboard.enable();
+    return;
+  }
+
+  map.dragPan.disable();
+  map.dragRotate.disable();
+  map.scrollZoom.disable();
+  map.touchZoomRotate.disable();
+  map.doubleClickZoom.disable();
+  map.keyboard.disable();
+}

src/components/map/camera-controller.tsx

@@ -1,15 +1,37 @@
 "use client";
 
-import { useEffect, useRef } from "react";
+import { useEffect, useRef, type MutableRefObject } from "react";
 import { useMap } from "./map";
+import {
+  FPV_DISTANCE_ZOOM_OFFSET,
+  fpvZoomForAltitude,
+  lerp,
+  lerpLng,
+  normalizeLng,
+  projectLngLatElevationPixelDelta,
+  setMapInteractionsEnabled,
+  smoothstep,
+} from "./camera-controller-utils";
 import { useSettings } from "@/hooks/use-settings";
 import type { City } from "@/lib/cities";
+import type { FlightState } from "@/lib/opensky";
 
 const IDLE_TIMEOUT_MS = 5_000;
 const ORBIT_EASE_IN_MS = 2000;
 const DEFAULT_ZOOM = 9.2;
 const DEFAULT_PITCH = 49;
 const DEFAULT_BEARING = 27.4;
+const FOLLOW_ZOOM = 10.5;
+const FOLLOW_PITCH = 55;
+const FOLLOW_EASE_MS = 1200;
+
+const FPV_FLY_DURATION = 1600;
+const FPV_PITCH = 65;
+const FPV_CENTER_ALPHA = 0.16;
+const FPV_BEARING_ALPHA = 0.1;
+const FPV_ZOOM_ALPHA = 0.06;
+const FPV_IDLE_RECENTER_MS = 1200;
+const FPV_EASE_IN_MS = 600;
 
 const CAMERA_ACCEL = 2.5;
 const CAMERA_DECEL = 4.0;
@@ -26,13 +48,39 @@ type ActionState = {
   impulseEnd: number;
 };
 
-export function CameraController({ city }: { city: City }) {
+type FpvPosition = { lng: number; lat: number; alt: number; track: number };
+
+export function CameraController({
+  city,
+  followFlight = null,
+  fpvFlight = null,
+  fpvPositionRef,
+}: {
+  city: City;
+  followFlight?: FlightState | null;
+  fpvFlight?: FlightState | null;
+  fpvPositionRef?: MutableRefObject<FpvPosition | null>;
+}) {
   const { map, isLoaded } = useMap();
   const { settings } = useSettings();
   const prevCityRef = useRef<string | null>(null);
+  const prevFollowRef = useRef<string | null>(null);
+  const prevFpvRef = useRef<string | null>(null);
   const idleTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const orbitFrameRef = useRef<number | null>(null);
   const isInteractingRef = useRef(false);
+  const isFollowingRef = useRef(false);
+  const isFpvActiveRef = useRef(false);
+  const fpvFlightRef = useRef<FlightState | null>(fpvFlight);
+  const fpvPosRef = useRef(fpvPositionRef);
+
+  useEffect(() => {
+    fpvPosRef.current = fpvPositionRef;
+  }, [fpvPositionRef]);
+
+  useEffect(() => {
+    fpvFlightRef.current = fpvFlight;
+  }, [fpvFlight]);
 
   useEffect(() => {
     if (!map || !isLoaded || !city) return;
@@ -49,10 +97,300 @@ export function CameraController({ city }: { city: City }) {
     });
   }, [map, isLoaded, city]);
 
+  useEffect(() => {
+    if (!map || !isLoaded) return;
+
+    const followKey = followFlight?.icao24 ?? null;
+    if (followKey === prevFollowRef.current) return;
+    prevFollowRef.current = followKey;
+
+    if (
+      !followFlight ||
+      followFlight.longitude == null ||
+      followFlight.latitude == null
+    ) {
+      isFollowingRef.current = false;
+      return;
+    }
+
+    isFollowingRef.current = true;
+    const bearing = Number.isFinite(followFlight.trueTrack)
+      ? followFlight.trueTrack!
+      : map.getBearing();
+
+    map.flyTo({
+      center: [followFlight.longitude, followFlight.latitude],
+      zoom: FOLLOW_ZOOM,
+      pitch: FOLLOW_PITCH,
+      bearing,
+      duration: 2200,
+      essential: true,
+    });
+  }, [map, isLoaded, followFlight]);
+
+  useEffect(() => {
+    if (!map || !isLoaded || !followFlight) return;
+    if (followFlight.longitude == null || followFlight.latitude == null) return;
+
+    if (!isFollowingRef.current) return;
+
+    map.easeTo({
+      center: [followFlight.longitude, followFlight.latitude],
+      bearing: Number.isFinite(followFlight.trueTrack)
+        ? followFlight.trueTrack!
+        : map.getBearing(),
+      duration: FOLLOW_EASE_MS,
+      essential: true,
+    });
+  }, [
+    map,
+    isLoaded,
+    followFlight,
+    followFlight?.longitude,
+    followFlight?.latitude,
+    followFlight?.trueTrack,
+  ]);
+
+  useEffect(() => {
+    if (!map || !isLoaded) {
+      if (isFpvActiveRef.current) {
+        isFpvActiveRef.current = false;
+      }
+      return;
+    }
+
+    const fpv = fpvFlightRef.current;
+    const fpvKey = fpv?.icao24 ?? null;
+    if (fpvKey === prevFpvRef.current) return;
+
+    const wasFpv = prevFpvRef.current !== null;
+    prevFpvRef.current = fpvKey;
+
+    if (!fpv || fpv.longitude == null || fpv.latitude == null) {
+      isFpvActiveRef.current = false;
+      if (wasFpv) {
+        setMapInteractionsEnabled(map, true);
+      }
+      if (wasFpv) {
+        map.flyTo({
+          center: city.coordinates,
+          zoom: DEFAULT_ZOOM,
+          pitch: DEFAULT_PITCH,
+          bearing: DEFAULT_BEARING,
+          duration: 1800,
+          essential: true,
+        });
+      }
+      return;
+    }
+
+    isFpvActiveRef.current = true;
+    setMapInteractionsEnabled(map, true);
+
+    const bearing = Number.isFinite(fpv.trueTrack)
+      ? fpv.trueTrack!
+      : map.getBearing();
+    const safeAltitude = Number.isFinite(fpv.baroAltitude)
+      ? fpv.baroAltitude!
+      : 5000;
+    const zoom = fpvZoomForAltitude(safeAltitude) - FPV_DISTANCE_ZOOM_OFFSET;
+
+    let fpvOffsetX = 0;
+    let fpvOffsetY = 0;
+
+    map.flyTo({
+      center: [normalizeLng(fpv.longitude), fpv.latitude],
+      zoom,
+      pitch: FPV_PITCH,
+      bearing,
+      duration: FPV_FLY_DURATION,
+      essential: true,
+    });
+
+    let frameId: number | null = null;
+    let startupTimer: ReturnType<typeof setTimeout> | null = null;
+    let prevBearing = bearing;
+
+    let lastInteractionTime = 0; // 0 = no interaction yet → track immediately
+    let recenterStartTime = 0;
+    let programmaticMove = false;
+
+    function onUserInteraction() {
+      if (programmaticMove) return;
+      lastInteractionTime = performance.now();
+      recenterStartTime = 0;
+    }
+
+    const onMapInteraction = (e: unknown) => {
+      if (programmaticMove) return;
+      const evt = e as { originalEvent?: Event };
+      if (!evt?.originalEvent) return;
+      onUserInteraction();
+    };
+
+    const interactionEventTypes = [
+      "movestart",
+      "move",
+      "zoomstart",
+      "zoom",
+      "rotatestart",
+      "rotate",
+      "pitchstart",
+      "pitch",
+    ] as const;
+
+    for (const t of interactionEventTypes) {
+      map.on(t, onMapInteraction);
+    }
+
+    function keepInFrame() {
+      if (!isFpvActiveRef.current || !map) {
+        frameId = null;
+        return;
+      }
+
+      const interpPos = fpvPosRef.current?.current ?? null;
+      const live = fpvFlightRef.current;
+
+      const posLng = interpPos?.lng ?? live?.longitude ?? null;
+      const posLat = interpPos?.lat ?? live?.latitude ?? null;
+      const posAlt = interpPos?.alt ?? live?.baroAltitude ?? 5000;
+      const posTrack = interpPos?.track ?? live?.trueTrack ?? null;
+
+      if (posLng == null || posLat == null) {
+        frameId = requestAnimationFrame(keepInFrame);
+        return;
+      }
+
+      if (
+        !Number.isFinite(posLng) ||
+        !Number.isFinite(posLat) ||
+        Math.abs(posLat) > 90
+      ) {
+        frameId = requestAnimationFrame(keepInFrame);
+        return;
+      }
+
+      const now = performance.now();
+      const idleMs =
+        lastInteractionTime === 0
+          ? FPV_IDLE_RECENTER_MS + 1
+          : now - lastInteractionTime;
+      const isIdle = idleMs > FPV_IDLE_RECENTER_MS;
+
+      let trackingStrength = 0;
+      if (isIdle) {
+        if (recenterStartTime === 0) {
+          recenterStartTime = now;
+        }
+        const easeElapsed = now - recenterStartTime;
+        const t = Math.min(easeElapsed / FPV_EASE_IN_MS, 1);
+        trackingStrength = smoothstep(t);
+      }
+
+      const liveBearing =
+        posTrack !== null && Number.isFinite(posTrack) ? posTrack : prevBearing;
+      const bearingDelta = ((liveBearing - prevBearing + 540) % 360) - 180;
+      prevBearing = prevBearing + bearingDelta * FPV_BEARING_ALPHA;
+
+      if (trackingStrength > 0.001) {
+        const safeAlt = Number.isFinite(posAlt) ? posAlt : 5000;
+        const targetZoom =
+          fpvZoomForAltitude(safeAlt) - FPV_DISTANCE_ZOOM_OFFSET;
+        const currentZoom = map.getZoom();
+        const zoomAlpha = FPV_ZOOM_ALPHA * trackingStrength;
+        const smoothZoom = lerp(currentZoom, targetZoom, zoomAlpha);
+
+        const currentPitch = map.getPitch();
+        const targetLng = normalizeLng(posLng);
+        const targetLat = posLat;
+        const center = map.getCenter();
+        const centerAlpha = FPV_CENTER_ALPHA * trackingStrength;
+
+        const canvas = map.getCanvas();
+        const canvasW = Math.max(1, canvas.clientWidth);
+        const canvasH = Math.max(1, canvas.clientHeight);
+
+        const elevationMeters = Math.max(safeAlt * 5, 200);
+        const deltaPx = projectLngLatElevationPixelDelta(
+          map,
+          targetLng,
+          targetLat,
+          elevationMeters,
+        );
+        if (deltaPx) {
+          const desiredX = fpvOffsetX - deltaPx.dx;
+          const desiredY = fpvOffsetY - deltaPx.dy;
+          const offsetAlpha = 0.08 * trackingStrength;
+          fpvOffsetX = lerp(fpvOffsetX, desiredX, offsetAlpha);
+          fpvOffsetY = lerp(fpvOffsetY, desiredY, offsetAlpha);
+        } else {
+          const decayAlpha = 0.1 * trackingStrength;
+          fpvOffsetX = lerp(fpvOffsetX, 0, decayAlpha);
+          fpvOffsetY = lerp(fpvOffsetY, 0, decayAlpha);
+        }
+
+        const maxScale = Math.min(1.5, Math.max(1, elevationMeters / 15_000));
+        const maxOffset = 0.45 * maxScale * Math.min(canvasW, canvasH);
+        fpvOffsetX = Math.max(-maxOffset, Math.min(maxOffset, fpvOffsetX));
+        fpvOffsetY = Math.max(-maxOffset, Math.min(maxOffset, fpvOffsetY));
+
+        const currentBearing = map.getBearing();
+        const bearingToCurrent =
+          ((prevBearing - currentBearing + 540) % 360) - 180;
+        const newMapBearing =
+          currentBearing +
+          bearingToCurrent * FPV_BEARING_ALPHA * trackingStrength;
+
+        const pitchAlpha = 0.05 * trackingStrength;
+        const newPitch = lerp(currentPitch, FPV_PITCH, pitchAlpha);
+
+        programmaticMove = true;
+        try {
+          map.easeTo({
+            center: [
+              lerpLng(center.lng, targetLng, centerAlpha),
+              lerp(center.lat, targetLat, centerAlpha),
+            ],
+            bearing: newMapBearing,
+            zoom: smoothZoom,
+            pitch: newPitch,
+            offset: [fpvOffsetX, fpvOffsetY],
+            duration: 0,
+            animate: false,
+            essential: true,
+          });
+        } finally {
+          programmaticMove = false;
+        }
+      }
+
+      frameId = requestAnimationFrame(keepInFrame);
+    }
+
+    startupTimer = setTimeout(() => {
+      startupTimer = null;
+      frameId = requestAnimationFrame(keepInFrame);
+    }, FPV_FLY_DURATION + 300);
+
+    return () => {
+      if (startupTimer) clearTimeout(startupTimer);
+      if (frameId != null) cancelAnimationFrame(frameId);
+      for (const t of interactionEventTypes) {
+        map.off(t, onMapInteraction);
+      }
+      if (map && isFpvActiveRef.current) {
+        setMapInteractionsEnabled(map, true);
+        isFpvActiveRef.current = false;
+      }
+    };
+  }, [map, isLoaded, fpvFlight?.icao24, city]);
+
   useEffect(() => {
     if (!map || !isLoaded || !city) return;
 
     const onNorthUp = () => {
+      if (isFpvActiveRef.current) return;
       map.easeTo({
         bearing: 0,
         duration: 650,
@@ -61,6 +399,7 @@ export function CameraController({ city }: { city: City }) {
     };
 
     const onResetView = (event: Event) => {
+      if (isFpvActiveRef.current) return;
       const customEvent = event as CustomEvent<{ center?: [number, number] }>;
       const center = customEvent.detail?.center ?? city.coordinates;
       map.flyTo({
@@ -167,6 +506,7 @@ export function CameraController({ city }: { city: City }) {
     }
 
     const onStart = (e: Event) => {
+      if (isFpvActiveRef.current) return;
       const { type, direction } = (e as CustomEvent).detail as {
         type: CameraActionType;
         direction: number;
@@ -201,7 +541,14 @@ export function CameraController({ city }: { city: City }) {
   }, [map, isLoaded]);
 
   useEffect(() => {
-    if (!map || !isLoaded || !city || !settings.autoOrbit) {
+    if (
+      !map ||
+      !isLoaded ||
+      !city ||
+      !settings.autoOrbit ||
+      followFlight ||
+      fpvFlight
+    ) {
       if (orbitFrameRef.current) cancelAnimationFrame(orbitFrameRef.current);
       if (idleTimerRef.current) clearTimeout(idleTimerRef.current);
       return;
@@ -224,7 +571,7 @@ export function CameraController({ city }: { city: City }) {
         if (!map || isInteractingRef.current) return;
         const resumeElapsed = performance.now() - resumeStart;
         const t = Math.min(resumeElapsed / ORBIT_EASE_IN_MS, 1);
-        const easeFactor = t * t * (3 - 2 * t);
+        const easeFactor = smoothstep(t);
         const bearing = map.getBearing() + speed * easeFactor;
         map.setBearing(bearing % 360);
         orbitFrameRef.current = requestAnimationFrame(tick);
@@ -290,6 +637,8 @@ export function CameraController({ city }: { city: City }) {
     map,
     isLoaded,
     city,
+    followFlight,
+    fpvFlight,
     settings.autoOrbit,
     settings.orbitSpeed,
     settings.orbitDirection,

src/components/map/flight-layers.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useEffect, useRef, useCallback } from "react";
+import { useEffect, useRef, useCallback, type MutableRefObject } from "react";
 import maplibregl from "maplibre-gl";
 import { MapboxOverlay } from "@deck.gl/mapbox";
 import { IconLayer, PathLayer } from "@deck.gl/layers";
@@ -11,7 +11,6 @@ import type { FlightState } from "@/lib/opensky";
 import { type TrailEntry } from "@/hooks/use-trail-history";
 import type { PickingInfo } from "@deck.gl/core";
 
-/** Typed overlay with deck.gl's pickObject capability */
 type DeckGLOverlay = MapboxOverlay & {
   pickObject?(opts: {
     x: number;
@@ -192,8 +191,9 @@ function getRingUrl(): string {
 function buildStartupFallbackTrail(f: FlightState): [number, number][] {
   if (f.longitude == null || f.latitude == null) return [];
 
-  const heading = ((f.trueTrack ?? 0) * Math.PI) / 180;
+  const heading =
-  const speed = f.velocity ?? 200;
+    ((Number.isFinite(f.trueTrack) ? f.trueTrack! : 0) * Math.PI) / 180;
+  const speed = Number.isFinite(f.velocity) ? f.velocity! : 200;
   const degPerSecond = speed / 111_320;
 
   const path: [number, number][] = [];
@@ -448,6 +448,13 @@ type FlightLayerProps = {
   trailDistance: number;
   showShadows: boolean;
   showAltitudeColors: boolean;
+  fpvIcao24?: string | null;
+  fpvPositionRef?: MutableRefObject<{
+    lng: number;
+    lat: number;
+    alt: number;
+    track: number;
+  } | null>;
 };
 
 export function FlightLayers({
@@ -460,6 +467,8 @@ export function FlightLayers({
   trailDistance,
   showShadows,
   showAltitudeColors,
+  fpvIcao24 = null,
+  fpvPositionRef,
 }: FlightLayerProps) {
   const { map, isLoaded } = useMap();
   const overlayRef = useRef<MapboxOverlay | null>(null);
@@ -481,6 +490,8 @@ export function FlightLayers({
   const showShadowsRef = useRef(showShadows);
   const showAltColorsRef = useRef(showAltitudeColors);
   const selectedIcao24Ref = useRef(selectedIcao24);
+  const fpvIcao24Ref = useRef(fpvIcao24);
+  const fpvPosRef = useRef(fpvPositionRef);
   const prevSelectedRef = useRef<string | null>(null);
   const selectionChangeTimeRef = useRef(0);
   const SELECTION_FADE_MS = 600;
@@ -493,6 +504,8 @@ export function FlightLayers({
     trailDistanceRef.current = trailDistance;
     showShadowsRef.current = showShadows;
     showAltColorsRef.current = showAltitudeColors;
+    fpvIcao24Ref.current = fpvIcao24;
+    fpvPosRef.current = fpvPositionRef;
     if (selectedIcao24 !== selectedIcao24Ref.current) {
       prevSelectedRef.current = selectedIcao24Ref.current;
       selectionChangeTimeRef.current = performance.now();
@@ -507,6 +520,8 @@ export function FlightLayers({
     showShadows,
     showAltitudeColors,
     selectedIcao24,
+    fpvIcao24,
+    fpvPositionRef,
   ]);
 
   useEffect(() => {
@@ -544,11 +559,12 @@ export function FlightLayers({
     for (const f of flights) {
       if (f.longitude != null && f.latitude != null) {
         const prev = newPrev.get(f.icao24);
-        const rawTrack = f.trueTrack ?? 0;
+        const rawTrack = Number.isFinite(f.trueTrack) ? f.trueTrack! : 0;
+        const rawAlt = Number.isFinite(f.baroAltitude) ? f.baroAltitude! : 0;
         next.set(f.icao24, {
           lng: f.longitude,
           lat: f.latitude,
-          alt: f.baroAltitude ?? 0,
+          alt: rawAlt,
           track:
             prev != null
               ? lerpAngle(prev.track, rawTrack, TRACK_DAMPING)
@@ -576,7 +592,6 @@ export function FlightLayers({
     [map],
   );
 
-  // Reset cursor if component unmounts while hovering.
   useEffect(() => {
     return () => {
       const canvas = map?.getCanvas();
@@ -674,7 +689,7 @@ export function FlightLayers({
           let prev = prevSnapshotsRef.current.get(f.icao24);
           if (!prev) {
             const rad = (curr.track * Math.PI) / 180;
-            const spd = f.velocity ?? 200;
+            const spd = Number.isFinite(f.velocity) ? f.velocity! : 200;
             const step = Math.min(
               (spd * (animDurationRef.current / 1000)) / 111_320,
               0.015,
@@ -705,7 +720,7 @@ export function FlightLayers({
           }
 
           const heading = (curr.track * Math.PI) / 180;
-          const speed = f.velocity ?? 200;
+          const speed = Number.isFinite(f.velocity) ? f.velocity! : 200;
           const extraSec = ((rawT - 1) * animDurationRef.current) / 1000;
           const extraDeg = Math.min((speed * extraSec) / 111_320, 0.03);
           const moveDx = Math.sin(heading) * extraDeg;
@@ -724,6 +739,33 @@ export function FlightLayers({
           interpolatedMap.set(f.icao24, f);
         }
 
+        const fpvId = fpvIcao24Ref.current?.toLowerCase() ?? null;
+        const visibleFlights = interpolated;
+
+        const fpvPosOut = fpvPosRef.current;
+        if (fpvPosOut && fpvId) {
+          const fpvF =
+            interpolated.find((f) => f.icao24.toLowerCase() === fpvId) ?? null;
+          if (
+            fpvF &&
+            Number.isFinite(fpvF.longitude) &&
+            Number.isFinite(fpvF.latitude)
+          ) {
+            fpvPosOut.current = {
+              lng: fpvF.longitude!,
+              lat: fpvF.latitude!,
+              alt: Number.isFinite(fpvF.baroAltitude)
+                ? fpvF.baroAltitude!
+                : 5000,
+              track: Number.isFinite(fpvF.trueTrack) ? fpvF.trueTrack! : 0,
+            };
+          } else {
+            fpvPosOut.current = null;
+          }
+        } else if (fpvPosOut && !fpvId) {
+          fpvPosOut.current = null;
+        }
+
         const pitchByIcao = new Map<string, number>();
         for (const f of interpolated) {
           const curr = currSnapshotsRef.current.get(f.icao24);
@@ -771,8 +813,10 @@ export function FlightLayers({
                 })()
               : 0;
 
-          const speed = f.velocity ?? 0;
+          const speed = Number.isFinite(f.velocity) ? f.velocity! : 0;
-          const verticalRate = f.verticalRate ?? 0;
+          const verticalRate = Number.isFinite(f.verticalRate)
+            ? f.verticalRate!
+            : 0;
           const kinematicPitch =
             speed > 0 ? (-Math.atan2(verticalRate, speed) * 180) / Math.PI : 0;
 
@@ -789,12 +833,13 @@ export function FlightLayers({
           layers.push(
             new IconLayer<FlightState>({
               id: "flight-shadows",
-              data: interpolated,
+              data: visibleFlights,
               getPosition: (d) => [d.longitude!, d.latitude!, 0],
               getIcon: () => "aircraft",
               getSize: (d) => 20 * categorySizeMultiplier(d.category),
-              getColor: [0, 0, 0, 60],
+              getColor: () => [0, 0, 0, 60],
-              getAngle: (d) => 360 - (d.trueTrack ?? 0),
+              getAngle: (d) =>
+                360 - (Number.isFinite(d.trueTrack) ? d.trueTrack! : 0),
               iconAtlas: atlasUrl,
               iconMapping: AIRCRAFT_ICON_MAPPING,
               billboard: false,
@@ -942,6 +987,7 @@ export function FlightLayers({
                 const animFlight = interpolatedMap.get(d.icao24);
                 const visiblePoints = getVisibleTrailPoints(d, animFlight);
                 const len = visiblePoints.length;
+
                 return visiblePoints.map((point, i) => {
                   const tVal = len > 1 ? i / (len - 1) : 1;
                   const fade = Math.pow(tVal, 1.65);
@@ -1058,7 +1104,7 @@ export function FlightLayers({
         layers.push(
           new ScenegraphLayer<FlightState>({
             id: "flight-aircraft",
-            data: interpolated,
+            data: visibleFlights,
             getPosition: (d) => [
               d.longitude!,
               d.latitude!,
@@ -1066,7 +1112,7 @@ export function FlightLayers({
             ],
             getOrientation: (d) => {
               const pitch = pitchByIcao.get(d.icao24) ?? 0;
-              const yaw = -(d.trueTrack ?? 0);
+              const yaw = -(Number.isFinite(d.trueTrack) ? d.trueTrack! : 0);
               return [pitch, yaw, 90];
             },
             getColor: (d) => {

src/components/ui/airport-search-input.tsx

@@ -0,0 +1,257 @@
+"use client";
+
+import { useState, useEffect, useRef, useMemo } from "react";
+import { motion, AnimatePresence } from "motion/react";
+import { Search, X, MapPin, ChevronRight } from "lucide-react";
+import { CITIES, type City } from "@/lib/cities";
+import { searchAirports, type Airport } from "@/lib/airports";
+import { ScrollArea } from "@/components/ui/scroll-area";
+
+type AirportSearchInputProps = {
+  placeholder?: string;
+  selected: Airport | null;
+  onSelect: (airport: Airport) => void;
+  onClear?: () => void;
+  autoFocus?: boolean;
+  label?: string;
+};
+
+export function AirportSearchInput({
+  placeholder = "Search airports...",
+  selected,
+  onSelect,
+  onClear,
+  autoFocus = false,
+  label = "Search airports",
+}: AirportSearchInputProps) {
+  const [query, setQuery] = useState("");
+  const [isOpen, setIsOpen] = useState(false);
+  const inputRef = useRef<HTMLInputElement>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (autoFocus) {
+      requestAnimationFrame(() => inputRef.current?.focus());
+    }
+  }, [autoFocus]);
+
+  useEffect(() => {
+    function handleClickOutside(e: MouseEvent) {
+      if (
+        containerRef.current &&
+        !containerRef.current.contains(e.target as Node)
+      ) {
+        setIsOpen(false);
+      }
+    }
+    document.addEventListener("mousedown", handleClickOutside);
+    return () => document.removeEventListener("mousedown", handleClickOutside);
+  }, []);
+
+  const { featured, airports } = useMemo(() => {
+    const q = query.trim().toLowerCase();
+
+    if (!q) {
+      return {
+        featured: CITIES.slice(0, 10),
+        airports: [] as ReturnType<typeof searchAirports>,
+      };
+    }
+
+    const featured = CITIES.filter(
+      (c) =>
+        c.name.toLowerCase().includes(q) ||
+        c.iata.toLowerCase().includes(q) ||
+        c.country.toLowerCase().includes(q),
+    );
+
+    const featuredIatas = new Set(CITIES.map((c) => c.iata));
+    const airports = searchAirports(q, 15).filter(
+      (a) => !featuredIatas.has(a.iata),
+    );
+
+    return { featured, airports };
+  }, [query]);
+
+  const hasResults = featured.length > 0 || airports.length > 0;
+
+  function handleSelect(airport: Airport) {
+    onSelect(airport);
+    setQuery("");
+    setIsOpen(false);
+  }
+
+  function handleSelectCity(city: City) {
+    const real = searchAirports(city.iata, 1).find((a) => a.iata === city.iata);
+    const airport: Airport = real ?? {
+      iata: city.iata,
+      name: city.name,
+      city: city.name,
+      country: city.country,
+      lat: city.coordinates[1],
+      lng: city.coordinates[0],
+    };
+    handleSelect(airport);
+  }
+
+  function handleClear() {
+    setQuery("");
+    onClear?.();
+    inputRef.current?.focus();
+  }
+
+  return (
+    <div ref={containerRef} className="relative">
+      {selected && !isOpen ? (
+        <button
+          onClick={() => {
+            setIsOpen(true);
+            requestAnimationFrame(() => inputRef.current?.focus());
+          }}
+          className="flex w-full items-center gap-2 rounded-xl border border-white/8 bg-white/4 px-3 py-2.5 text-left transition-colors hover:bg-white/6"
+        >
+          <div className="flex h-6 w-6 items-center justify-center rounded-md bg-white/8">
+            <MapPin className="h-3 w-3 text-white/50" />
+          </div>
+          <div className="flex-1 min-w-0">
+            <span className="text-[13px] font-semibold text-white/80">
+              {selected.iata}
+            </span>
+            <span className="ml-1.5 text-[11px] text-white/30">
+              {selected.city}
+            </span>
+          </div>
+          {onClear && (
+            <button
+              onClick={(e) => {
+                e.stopPropagation();
+                handleClear();
+              }}
+              className="shrink-0 text-white/20 hover:text-white/40 transition-colors"
+              aria-label="Clear selection"
+            >
+              <X className="h-3 w-3" />
+            </button>
+          )}
+        </button>
+      ) : (
+        <div className="flex items-center gap-2 rounded-xl border border-white/8 bg-white/4 px-3 py-2">
+          <Search className="h-3.5 w-3.5 shrink-0 text-white/25" />
+          <input
+            ref={inputRef}
+            value={query}
+            onChange={(e) => {
+              setQuery(e.target.value);
+              setIsOpen(true);
+            }}
+            onFocus={() => setIsOpen(true)}
+            placeholder={placeholder}
+            aria-label={label}
+            className="flex-1 bg-transparent text-[13px] font-medium text-white/90 placeholder:text-white/20 outline-none"
+          />
+          {query && (
+            <button
+              onClick={() => setQuery("")}
+              className="shrink-0 text-white/20 hover:text-white/40 transition-colors"
+              aria-label="Clear search"
+            >
+              <X className="h-3 w-3" />
+            </button>
+          )}
+        </div>
+      )}
+
+      <AnimatePresence>
+        {isOpen && (
+          <motion.div
+            initial={{ opacity: 0, y: -4, scale: 0.98 }}
+            animate={{ opacity: 1, y: 0, scale: 1 }}
+            exit={{ opacity: 0, y: -4, scale: 0.98 }}
+            transition={{ duration: 0.15 }}
+            className="absolute left-0 right-0 top-full z-50 mt-1 overflow-hidden rounded-xl border border-white/8 bg-[#0c0c0e]/95 shadow-[0_20px_60px_rgba(0,0,0,.7)] backdrop-blur-2xl"
+          >
+            <ScrollArea className="max-h-56">
+              <div className="p-1.5">
+                {!hasResults && (
+                  <p className="py-6 text-center text-[11px] text-white/25">
+                    No airports found
+                  </p>
+                )}
+
+                {featured.length > 0 && (
+                  <>
+                    {query && (
+                      <p className="px-2.5 pt-1.5 pb-1 text-[9px] font-semibold uppercase tracking-widest text-white/15">
+                        Featured
+                      </p>
+                    )}
+                    {featured.map((city) => (
+                      <DropdownRow
+                        key={city.id}
+                        name={city.name}
+                        detail={`${city.iata} · ${city.country}`}
+                        isActive={selected?.iata === city.iata}
+                        onClick={() => handleSelectCity(city)}
+                      />
+                    ))}
+                  </>
+                )}
+
+                {airports.length > 0 && (
+                  <>
+                    <p
+                      className={`px-2.5 pb-1 text-[9px] font-semibold uppercase tracking-widest text-white/15 ${
+                        featured.length > 0 ? "pt-2" : "pt-1.5"
+                      }`}
+                    >
+                      Airports
+                    </p>
+                    {airports.map((airport) => (
+                      <DropdownRow
+                        key={airport.iata}
+                        name={airport.name}
+                        detail={`${airport.iata} · ${airport.city}, ${airport.country}`}
+                        isActive={selected?.iata === airport.iata}
+                        onClick={() => handleSelect(airport)}
+                      />
+                    ))}
+                  </>
+                )}
+              </div>
+            </ScrollArea>
+          </motion.div>
+        )}
+      </AnimatePresence>
+    </div>
+  );
+}
+
+function DropdownRow({
+  name,
+  detail,
+  isActive,
+  onClick,
+}: {
+  name: string;
+  detail: string;
+  isActive: boolean;
+  onClick: () => void;
+}) {
+  return (
+    <button
+      onClick={onClick}
+      className={`group flex w-full items-center gap-2 rounded-lg px-2.5 py-2 text-left transition-colors hover:bg-white/5 ${
+        isActive ? "bg-white/6" : ""
+      }`}
+    >
+      <div className="flex h-6 w-6 shrink-0 items-center justify-center rounded-md bg-white/4">
+        <MapPin className="h-3 w-3 text-white/35" />
+      </div>
+      <div className="flex-1 min-w-0">
+        <p className="truncate text-[12px] font-medium text-white/75">{name}</p>
+        <p className="text-[10px] text-white/25">{detail}</p>
+      </div>
+      <ChevronRight className="h-3 w-3 shrink-0 text-white/10 group-hover:text-white/20" />
+    </button>
+  );
+}

src/components/ui/control-panel.tsx

@@ -17,6 +17,9 @@ import {
   Palette,
   ArrowLeftRight,
   Github,
+  Plane,
+  Eye,
+  Loader2,
 } from "lucide-react";
 import { CITIES, type City } from "@/lib/cities";
 import { searchAirports, airportToCity } from "@/lib/airports";
@@ -24,6 +27,8 @@ import { MAP_STYLES, type MapStyle } from "@/lib/map-styles";
 import { useSettings, type OrbitDirection } from "@/hooks/use-settings";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { Slider } from "@/components/ui/slider";
+import type { FlightState } from "@/lib/opensky";
+import { formatCallsign } from "@/lib/flight-utils";
 
 type TabId = "search" | "style" | "settings";
 
@@ -38,6 +43,9 @@ type ControlPanelProps = {
   onSelectCity: (city: City) => void;
   activeStyle: MapStyle;
   onSelectStyle: (style: MapStyle) => void;
+  flights: FlightState[];
+  activeFlightIcao24: string | null;
+  onLookupFlight: (query: string, enterFpv?: boolean) => Promise<boolean>;
 };
 
 export function ControlPanel({
@@ -45,6 +53,9 @@ export function ControlPanel({
   onSelectCity,
   activeStyle,
   onSelectStyle,
+  flights,
+  activeFlightIcao24,
+  onLookupFlight,
 }: ControlPanelProps) {
   const [openTab, setOpenTab] = useState<TabId | null>(null);
 
@@ -94,6 +105,9 @@ export function ControlPanel({
             }}
             activeStyle={activeStyle}
             onSelectStyle={onSelectStyle}
+            flights={flights}
+            activeFlightIcao24={activeFlightIcao24}
+            onLookupFlight={onLookupFlight}
           />
         )}
       </AnimatePresence>
@@ -109,6 +123,9 @@ function PanelDialog({
   onSelectCity,
   activeStyle,
   onSelectStyle,
+  flights,
+  activeFlightIcao24,
+  onLookupFlight,
 }: {
   activeTab: TabId;
   onTabChange: (tab: TabId) => void;
@@ -117,6 +134,9 @@ function PanelDialog({
   onSelectCity: (city: City) => void;
   activeStyle: MapStyle;
   onSelectStyle: (style: MapStyle) => void;
+  flights: FlightState[];
+  activeFlightIcao24: string | null;
+  onLookupFlight: (query: string, enterFpv?: boolean) => Promise<boolean>;
 }) {
   const dialogRef = useRef<HTMLDivElement>(null);
 
@@ -246,7 +266,7 @@ function PanelDialog({
               </a>
               <div className="border-t border-white/3 pt-2 px-2.5">
                 <p className="text-[10px] font-medium text-white/10 tracking-wide">
-                  v0.1 \u00b7 OpenSky Network
+                  v0.1 · OpenSky Network
                 </p>
               </div>
             </div>
@@ -288,6 +308,13 @@ function PanelDialog({
                     <SearchContent
                       activeCity={activeCity}
                       onSelect={onSelectCity}
+                      flights={flights}
+                      activeFlightIcao24={activeFlightIcao24}
+                      onLookupFlight={async (query, enterFpv = false) => {
+                        const found = await onLookupFlight(query, enterFpv);
+                        if (found) onClose();
+                        return found;
+                      }}
                     />
                   </TabContent>
                 )}
@@ -374,11 +401,19 @@ function TabContent({ children }: { children: ReactNode }) {
 function SearchContent({
   activeCity,
   onSelect,
+  flights,
+  activeFlightIcao24,
+  onLookupFlight,
 }: {
   activeCity: City;
   onSelect: (city: City) => void;
+  flights: FlightState[];
+  activeFlightIcao24: string | null;
+  onLookupFlight: (query: string, enterFpv?: boolean) => Promise<boolean>;
 }) {
   const [query, setQuery] = useState("");
+  const [lookupBusy, setLookupBusy] = useState(false);
+  const [lookupError, setLookupError] = useState<string | null>(null);
   const inputRef = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
@@ -409,7 +444,58 @@ function SearchContent({
     return { featured, airports };
   }, [query]);
 
-  const hasResults = featured.length > 0 || airports.length > 0;
+  const normalizedQuery = query.trim().toLowerCase();
+  const compactQuery = normalizedQuery.replace(/\s+/g, "");
+  const isIcao24Query = /^[0-9a-f]{6}$/.test(compactQuery);
+
+  const flightMatches = useMemo(() => {
+    if (!compactQuery) return [] as FlightState[];
+    return flights
+      .filter((flight) => {
+        const icao = flight.icao24.toLowerCase();
+        const callsign = (flight.callsign ?? "")
+          .trim()
+          .toLowerCase()
+          .replace(/\s+/g, "");
+        return icao.includes(compactQuery) || callsign.includes(compactQuery);
+      })
+      .slice(0, 12);
+  }, [flights, compactQuery]);
+
+  const hasResults =
+    featured.length > 0 || airports.length > 0 || flightMatches.length > 0;
+
+  async function runLookup(enterFpv = false) {
+    if (!query.trim() || lookupBusy) return;
+    setLookupBusy(true);
+    setLookupError(null);
+    try {
+      const found = await onLookupFlight(query, enterFpv);
+      if (!found) {
+        setLookupError(
+          isIcao24Query
+            ? "Flight not found for this ICAO24 right now"
+            : "No live worldwide flight match found (or rate-limited)",
+        );
+      }
+    } finally {
+      setLookupBusy(false);
+    }
+  }
+
+  async function openFlight(icao24: string, enterFpv = false) {
+    if (lookupBusy) return;
+    setLookupBusy(true);
+    setLookupError(null);
+    try {
+      const found = await onLookupFlight(icao24, enterFpv);
+      if (!found) {
+        setLookupError("Unable to open the selected flight");
+      }
+    } finally {
+      setLookupBusy(false);
+    }
+  }
 
   return (
     <div className="flex h-full flex-col">
@@ -418,9 +504,18 @@ function SearchContent({
         <input
           ref={inputRef}
           value={query}
-          onChange={(e) => setQuery(e.target.value)}
+          onChange={(e) => {
-          placeholder="Search airports..."
+            setQuery(e.target.value);
-          aria-label="Search airports by name, IATA code, city, or country"
+            setLookupError(null);
+          }}
+          onKeyDown={(e) => {
+            if (e.key === "Enter") {
+              e.preventDefault();
+              void runLookup(false);
+            }
+          }}
+          placeholder="Search airports or flight number (callsign/ICAO24)..."
+          aria-label="Search airports by name, IATA code, city, country, or flight callsign/ICAO24"
           className="flex-1 bg-transparent text-[14px] font-medium text-white/90 placeholder:text-white/20 outline-none"
         />
         {query && (
@@ -436,9 +531,64 @@ function SearchContent({
 
       <ScrollArea className="flex-1">
         <div className="p-2">
+          {compactQuery && (
+            <div className="px-3 pb-2 space-y-2">
+              <button
+                type="button"
+                onClick={() => void runLookup(false)}
+                disabled={lookupBusy}
+                className="flex w-full items-center justify-center gap-2 rounded-lg border border-white/10 bg-white/4 px-3 py-2 text-[12px] font-medium text-white/75 transition-colors hover:bg-white/7 disabled:cursor-not-allowed disabled:opacity-60"
+              >
+                {lookupBusy ? (
+                  <Loader2 className="h-3.5 w-3.5 animate-spin" />
+                ) : (
+                  <Search className="h-3.5 w-3.5" />
+                )}
+                <span>Open Flight Details</span>
+              </button>
+              <button
+                type="button"
+                onClick={() => void runLookup(true)}
+                disabled={lookupBusy}
+                className="flex w-full items-center justify-center gap-2 rounded-lg border border-sky-400/25 bg-sky-500/10 px-3 py-2 text-[12px] font-medium text-sky-300/90 transition-colors hover:bg-sky-500/15 disabled:cursor-not-allowed disabled:opacity-60"
+              >
+                {lookupBusy ? (
+                  <Loader2 className="h-3.5 w-3.5 animate-spin" />
+                ) : (
+                  <Eye className="h-3.5 w-3.5" />
+                )}
+                <span>Open in FPV</span>
+              </button>
+            </div>
+          )}
+
+          {lookupError && (
+            <p className="px-3 pb-2 text-[11px] font-medium text-amber-300/85">
+              {lookupError}
+            </p>
+          )}
+
+          {flightMatches.length > 0 && (
+            <>
+              <p className="px-3 pt-1 pb-1.5 text-[10px] font-semibold uppercase tracking-widest text-white/15">
+                Flights
+              </p>
+              {flightMatches.map((flight) => (
+                <FlightRow
+                  key={flight.icao24}
+                  callsign={formatCallsign(flight.callsign)}
+                  detail={`${flight.icao24.toUpperCase()} · ${flight.originCountry}`}
+                  isActive={activeFlightIcao24 === flight.icao24}
+                  onOpen={() => void openFlight(flight.icao24, false)}
+                  onFpv={() => void openFlight(flight.icao24, true)}
+                />
+              ))}
+            </>
+          )}
+
           {!hasResults && (
             <p className="py-8 text-center text-[12px] text-white/25">
-              No airports found
+              No airports or flights found
             </p>
           )}
 
@@ -453,7 +603,7 @@ function SearchContent({
                 <LocationRow
                   key={city.id}
                   name={city.name}
-                  detail={`${city.iata} \u00b7 ${city.country}`}
+                  detail={`${city.iata} · ${city.country}`}
                   isActive={activeCity?.id === city.id}
                   onClick={() => onSelect(city)}
                 />
@@ -474,7 +624,7 @@ function SearchContent({
                 <LocationRow
                   key={airport.iata}
                   name={airport.name}
-                  detail={`${airport.iata} \u00b7 ${airport.city}, ${airport.country}`}
+                  detail={`${airport.iata} · ${airport.city}, ${airport.country}`}
                   isActive={activeCity?.iata === airport.iata}
                   onClick={() => onSelect(airportToCity(airport))}
                 />
@@ -524,6 +674,52 @@ function LocationRow({
   );
 }
 
+function FlightRow({
+  callsign,
+  detail,
+  isActive,
+  onOpen,
+  onFpv,
+}: {
+  callsign: string;
+  detail: string;
+  isActive: boolean;
+  onOpen: () => void;
+  onFpv: () => void;
+}) {
+  return (
+    <div
+      className={`group flex items-center gap-2.5 rounded-xl px-3 py-2.5 transition-colors hover:bg-white/4 ${
+        isActive ? "bg-white/6" : ""
+      }`}
+    >
+      <button
+        onClick={onOpen}
+        className="flex min-w-0 flex-1 items-center gap-2.5 text-left"
+      >
+        <div className="flex h-8 w-8 shrink-0 items-center justify-center rounded-lg bg-white/4">
+          <Plane className="h-3.5 w-3.5 text-white/40" />
+        </div>
+        <div className="min-w-0 flex-1">
+          <p className="truncate text-[14px] font-medium text-white/80">
+            {callsign}
+          </p>
+          <p className="text-[11px] font-medium text-white/25">{detail}</p>
+        </div>
+      </button>
+      <button
+        type="button"
+        onClick={onFpv}
+        className="inline-flex h-7 items-center gap-1.5 rounded-lg border border-sky-400/20 bg-sky-500/10 px-2 text-[10px] font-semibold uppercase tracking-wide text-sky-300/90 transition-colors hover:bg-sky-500/20"
+        aria-label="Open flight in FPV"
+      >
+        <Eye className="h-3 w-3" />
+        FPV
+      </button>
+    </div>
+  );
+}
+
 function StyleContent({
   activeStyle,
   onSelect,
@@ -546,8 +742,7 @@ function StyleContent({
       </div>
       <div className="border-t border-white/4 px-5 py-3">
         <p className="text-[11px] font-medium text-white/12">
-          Satellite \u00a9 Esri \u00b7 Terrain \u00a9 OpenTopoMap \u00b7 Base
+          Satellite © Esri · Terrain © OpenTopoMap · Base maps © CARTO
-          maps \u00a9 CARTO
         </p>
       </div>
     </ScrollArea>
@@ -594,6 +789,7 @@ function StyleTile({
           fill
           unoptimized
           onLoad={() => setImgLoaded(true)}
+          onError={() => setImgLoaded(true)}
           className={`object-cover transition-all duration-500 group-hover:scale-105 ${
             imgLoaded ? "opacity-100" : "opacity-0"
           }`}
@@ -747,7 +943,7 @@ function OrbitSpeedSlider({
   const activeLabel =
     ORBIT_SPEED_PRESETS.find(
       (p) => Math.abs(p.value - value) < ORBIT_SNAP_THRESHOLD,
-    )?.label ?? `${value.toFixed(2)}\u00d7`;
+    )?.label ?? `${value.toFixed(2)}×`;
 
   function handleChange(vals: number[]) {
     let raw = vals[0];

src/components/ui/flight-card.tsx

@@ -13,6 +13,7 @@ import {
   X,
   Navigation,
   Building2,
+  Eye,
 } from "lucide-react";
 import type { FlightState } from "@/lib/opensky";
 import {
@@ -28,11 +29,18 @@ import { airlineLogoCandidates } from "@/lib/airline-logos";
 type FlightCardProps = {
   flight: FlightState | null;
   onClose: () => void;
+  onToggleFpv?: (icao24: string) => void;
+  isFpvActive?: boolean;
 };
 
 const loadedLogoUrls = new Set<string>();
 
-export function FlightCard({ flight, onClose }: FlightCardProps) {
+export function FlightCard({
+  flight,
+  onClose,
+  onToggleFpv,
+  isFpvActive = false,
+}: FlightCardProps) {
   const airline = flight ? lookupAirline(flight.callsign) : null;
   const flightNum = flight ? parseFlightNumber(flight.callsign) : null;
   const company =
@@ -41,6 +49,11 @@ export function FlightCard({ flight, onClose }: FlightCardProps) {
   const logoCandidates = airlineLogoCandidates(airline);
   const heading = flight?.trueTrack ?? null;
   const cardinal = heading !== null ? headingToCardinal(heading) : null;
+  const canEnterFpv =
+    flight != null &&
+    flight.longitude != null &&
+    flight.latitude != null &&
+    !flight.onGround;
   const [logoIndexByAirline, setLogoIndexByAirline] = useState<
     Record<string, number>
   >({});
@@ -132,15 +145,56 @@ export function FlightCard({ flight, onClose }: FlightCardProps) {
                   </p>
                 </div>
               </div>
-              <motion.button
+              <div className="flex items-center gap-1.5">
-                onClick={onClose}
+                {onToggleFpv && (
-                className="flex h-6 w-6 items-center justify-center rounded-full bg-white/6 transition-colors hover:bg-white/12"
+                  <motion.button
-                whileHover={{ scale: 1.1 }}
+                    onClick={() =>
-                whileTap={{ scale: 0.9 }}
+                      (isFpvActive || canEnterFpv) &&
-                aria-label="Deselect flight"
+                      flight &&
-              >
+                      onToggleFpv(flight.icao24)
-                <X className="h-3 w-3 text-white/40" />
+                    }
-              </motion.button>
+                    disabled={!isFpvActive && !canEnterFpv}
+                    className={`flex h-6 w-6 items-center justify-center rounded-full transition-colors ${
+                      isFpvActive
+                        ? "bg-emerald-500/20 text-emerald-400"
+                        : !canEnterFpv
+                          ? "bg-white/4 text-white/15 cursor-not-allowed"
+                          : "bg-white/6 text-white/40 hover:bg-white/12"
+                    }`}
+                    whileHover={
+                      isFpvActive || canEnterFpv ? { scale: 1.1 } : {}
+                    }
+                    whileTap={isFpvActive || canEnterFpv ? { scale: 0.9 } : {}}
+                    aria-label={
+                      isFpvActive
+                        ? "Exit first person view"
+                        : canEnterFpv
+                          ? "First person view"
+                          : "First person view unavailable"
+                    }
+                    title={
+                      isFpvActive
+                        ? "Exit FPV (F)"
+                        : canEnterFpv
+                          ? "First Person View (F)"
+                          : flight?.onGround
+                            ? "FPV unavailable (aircraft on ground)"
+                            : "FPV unavailable (no position data)"
+                    }
+                  >
+                    <Eye className="h-3 w-3" />
+                  </motion.button>
+                )}
+                <motion.button
+                  onClick={onClose}
+                  className="flex h-6 w-6 items-center justify-center rounded-full bg-white/6 transition-colors hover:bg-white/12"
+                  whileHover={{ scale: 1.1 }}
+                  whileTap={{ scale: 0.9 }}
+                  aria-label="Deselect flight"
+                >
+                  <X className="h-3 w-3 text-white/40" />
+                </motion.button>
+              </div>
             </div>
 
             {company && (
@@ -172,14 +226,17 @@ export function FlightCard({ flight, onClose }: FlightCardProps) {
                 icon={<Compass className="h-3 w-3" />}
                 label="Heading"
                 value={
-                  heading !== null ? `${Math.round(heading)}° ${cardinal}` : "—"
+                  heading !== null && Number.isFinite(heading)
+                    ? `${Math.round(heading)}° ${cardinal}`
+                    : "—"
                 }
               />
               <Metric
                 icon={<ArrowDown className="h-3 w-3" />}
                 label="V/S"
                 value={
-                  flight.verticalRate !== null
+                  flight.verticalRate !== null &&
+                  Number.isFinite(flight.verticalRate)
                     ? `${flight.verticalRate > 0 ? "+" : ""}${Math.round(flight.verticalRate)} m/s`
                     : "—"
                 }
@@ -201,20 +258,25 @@ export function FlightCard({ flight, onClose }: FlightCardProps) {
                     className="h-3 w-3 text-white/25"
                     style={{
                       transform:
-                        heading !== null ? `rotate(${heading}deg)` : undefined,
+                        heading !== null && Number.isFinite(heading)
+                          ? `rotate(${heading}deg)`
+                          : undefined,
                     }}
                   />
                   <p className="text-[11px] font-medium tracking-wide text-white/40">
                     Heading {cardinal}
-                    {flight.latitude !== null && flight.longitude !== null && (
+                    {flight.latitude !== null &&
-                      <span className="text-white/20">
+                      flight.longitude !== null &&
-                        {" "}
+                      Number.isFinite(flight.latitude) &&
-                        · {Math.abs(flight.latitude).toFixed(2)}°
+                      Number.isFinite(flight.longitude) && (
-                        {flight.latitude >= 0 ? "N" : "S"},{" "}
+                        <span className="text-white/20">
-                        {Math.abs(flight.longitude).toFixed(2)}°
+                          {" "}
-                        {flight.longitude >= 0 ? "E" : "W"}
+                          · {Math.abs(flight.latitude).toFixed(2)}°
-                      </span>
+                          {flight.latitude >= 0 ? "N" : "S"},{" "}
-                    )}
+                          {Math.abs(flight.longitude).toFixed(2)}°
+                          {flight.longitude >= 0 ? "E" : "W"}
+                        </span>
+                      )}
                   </p>
                 </div>
               )}

src/components/ui/fpv-hud.tsx

@@ -0,0 +1,272 @@
+"use client";
+
+import { useRef, useEffect, useMemo, useState } from "react";
+import Image from "next/image";
+import { motion } from "motion/react";
+import { X, Eye, ArrowUp, ArrowDown, Minus, Gauge } from "lucide-react";
+import type { FlightState } from "@/lib/opensky";
+import { formatCallsign, headingToCardinal } from "@/lib/flight-utils";
+import { lookupAirline } from "@/lib/airlines";
+import { airlineLogoCandidates } from "@/lib/airline-logos";
+
+type FpvHudProps = {
+  flight: FlightState;
+  onExit: () => void;
+};
+
+const COMPASS_LABELS: Record<number, string> = {
+  0: "N",
+  45: "NE",
+  90: "E",
+  135: "SE",
+  180: "S",
+  225: "SW",
+  270: "W",
+  315: "NW",
+};
+
+function CompassRibbon({ heading }: { heading: number | null }) {
+  const canvasRef = useRef<HTMLCanvasElement>(null);
+
+  useEffect(() => {
+    const canvas = canvasRef.current;
+    if (!canvas) return;
+    const ctx = canvas.getContext("2d");
+    if (!ctx) return;
+
+    const dpr = window.devicePixelRatio ?? 1;
+    const w = 260;
+    const h = 32;
+    canvas.width = w * dpr;
+    canvas.height = h * dpr;
+    canvas.style.width = `${w}px`;
+    canvas.style.height = `${h}px`;
+    ctx.scale(dpr, dpr);
+
+    ctx.clearRect(0, 0, w, h);
+
+    const hdg = heading ?? 0;
+    const cx = w / 2;
+    const pxPerDeg = 2.2;
+    for (let deg = -360; deg <= 720; deg += 5) {
+      const normDeg = ((deg % 360) + 360) % 360;
+      const offset = (((deg - hdg + 540) % 360) - 180) * pxPerDeg;
+      const x = cx + offset;
+
+      if (x < -10 || x > w + 10) continue;
+
+      const isMajor = normDeg % 45 === 0;
+      const isMinor = normDeg % 15 === 0;
+      const isTiny = normDeg % 5 === 0;
+
+      if (isMajor) {
+        ctx.strokeStyle = "rgba(255,255,255,0.45)";
+        ctx.lineWidth = 1.5;
+        ctx.beginPath();
+        ctx.moveTo(x, h - 1);
+        ctx.lineTo(x, h - 10);
+        ctx.stroke();
+
+        const label = COMPASS_LABELS[normDeg] ?? `${normDeg}`;
+        ctx.fillStyle = "rgba(255,255,255,0.55)";
+        ctx.font = "bold 9px Inter, system-ui, sans-serif";
+        ctx.textAlign = "center";
+        ctx.fillText(label, x, h - 14);
+      } else if (isMinor) {
+        ctx.strokeStyle = "rgba(255,255,255,0.22)";
+        ctx.lineWidth = 1;
+        ctx.beginPath();
+        ctx.moveTo(x, h - 1);
+        ctx.lineTo(x, h - 7);
+        ctx.stroke();
+      } else if (isTiny) {
+        ctx.strokeStyle = "rgba(255,255,255,0.10)";
+        ctx.lineWidth = 0.5;
+        ctx.beginPath();
+        ctx.moveTo(x, h - 1);
+        ctx.lineTo(x, h - 4);
+        ctx.stroke();
+      }
+    }
+
+    ctx.fillStyle = "rgba(56, 189, 248, 0.8)";
+    ctx.beginPath();
+    ctx.moveTo(cx - 4, 0);
+    ctx.lineTo(cx + 4, 0);
+    ctx.lineTo(cx, 6);
+    ctx.closePath();
+    ctx.fill();
+
+    ctx.strokeStyle = "rgba(56, 189, 248, 0.4)";
+    ctx.lineWidth = 1;
+    ctx.beginPath();
+    ctx.moveTo(cx, 6);
+    ctx.lineTo(cx, h);
+    ctx.stroke();
+  }, [heading]);
+
+  return (
+    <canvas
+      ref={canvasRef}
+      className="block"
+      style={{ width: 260, height: 32 }}
+      aria-label={
+        heading !== null ? `Heading ${Math.round(heading)}°` : "No heading data"
+      }
+    />
+  );
+}
+
+export function FpvHud({ flight, onExit }: FpvHudProps) {
+  const altFeet =
+    flight.baroAltitude !== null && Number.isFinite(flight.baroAltitude)
+      ? Math.round(flight.baroAltitude * 3.28084)
+      : null;
+  const speedKts =
+    flight.velocity !== null && Number.isFinite(flight.velocity)
+      ? Math.round(flight.velocity * 1.944)
+      : null;
+  const heading =
+    flight.trueTrack !== null && Number.isFinite(flight.trueTrack)
+      ? flight.trueTrack
+      : null;
+  const cardinal = heading !== null ? headingToCardinal(heading) : null;
+  const vs = flight.verticalRate;
+  const vsFpm =
+    vs !== null && Number.isFinite(vs) ? Math.round(vs * 196.85) : null;
+  const vsDisplay = vsFpm !== null ? `${vsFpm > 0 ? "+" : ""}${vsFpm}` : null;
+  const airline = useMemo(
+    () => lookupAirline(flight.callsign),
+    [flight.callsign],
+  );
+  const logoUrl = useMemo(() => {
+    return airlineLogoCandidates(airline)[0] ?? null;
+  }, [airline]);
+  const [logoErrorUrl, setLogoErrorUrl] = useState<string | null>(null);
+  const logoError = logoUrl !== null && logoUrl === logoErrorUrl;
+  const vsIcon =
+    vs !== null && Number.isFinite(vs) ? (
+      vs > 0.5 ? (
+        <ArrowUp className="h-3 w-3" />
+      ) : vs < -0.5 ? (
+        <ArrowDown className="h-3 w-3" />
+      ) : (
+        <Minus className="h-3 w-3" />
+      )
+    ) : null;
+
+  return (
+    <motion.div
+      initial={{ opacity: 0, y: 12 }}
+      animate={{ opacity: 1, y: 0 }}
+      exit={{ opacity: 0, y: 12 }}
+      transition={{ type: "spring", stiffness: 400, damping: 30 }}
+      className="pointer-events-auto fixed bottom-[calc(1.5rem+env(safe-area-inset-bottom))] left-1/2 z-50 -translate-x-1/2 sm:bottom-[calc(1.5rem+env(safe-area-inset-bottom))]"
+    >
+      <div
+        className="flex w-[min(92vw,460px)] flex-col items-center gap-0 overflow-hidden rounded-xl border border-white/8 bg-black/70 pb-1 shadow-[0_8px_32px_rgba(0,0,0,0.6)] backdrop-blur-3xl md:w-max"
+        role="status"
+        aria-live="polite"
+        aria-label="First person view flight instruments"
+      >
+        <div className="w-full border-b border-white/6 px-2 pt-1.5 pb-0.5 sm:px-2.5">
+          <div
+            className="mx-auto w-fit overflow-hidden rounded-md"
+            style={{ width: 260 }}
+          >
+            <CompassRibbon heading={heading} />
+          </div>
+          <p className="mt-0 text-center text-[10px] font-bold tabular-nums text-sky-400/70">
+            {heading !== null ? `${Math.round(heading)}° ${cardinal}` : "—"}
+          </p>
+        </div>
+
+        <div className="flex w-full items-stretch">
+          <div className="flex min-w-0 flex-1 items-center gap-2 border-r border-white/6 px-2 py-1.5 sm:px-3 sm:py-2">
+            {logoUrl && !logoError ? (
+              <span className="relative flex h-8 w-8 shrink-0 items-center justify-center overflow-hidden rounded-full bg-white/95 shadow-sm ring-1 ring-white/20">
+                <Image
+                  src={logoUrl}
+                  alt={airline ? `${airline} logo` : "Airline logo"}
+                  fill
+                  sizes="32px"
+                  className="object-contain p-1"
+                  unoptimized
+                  onError={() => setLogoErrorUrl(logoUrl)}
+                />
+              </span>
+            ) : (
+              <span className="flex h-8 w-8 shrink-0 items-center justify-center rounded-full bg-white/5 ring-1 ring-white/10">
+                <Eye className="h-3.5 w-3.5 text-emerald-400/70 animate-pulse" />
+              </span>
+            )}
+            <div className="min-w-0">
+              <p className="truncate text-[12px] font-bold tracking-wide text-white/90 sm:text-[13px]">
+                {formatCallsign(flight.callsign)}
+              </p>
+              <p className="truncate text-[9px] font-medium uppercase tracking-widest text-white/30">
+                {airline ?? flight.originCountry}
+              </p>
+            </div>
+          </div>
+
+          <div className="flex min-w-12 flex-col items-center justify-center border-r border-white/6 px-2.5 py-1.5 sm:min-w-16 sm:px-2.5">
+            <div className="flex items-center gap-0.5 text-white/30">
+              <ArrowUp className="h-2 w-2" />
+              <span className="text-[8px] font-semibold uppercase tracking-wider">
+                ALT
+              </span>
+            </div>
+            <p className="text-[13px] font-bold tabular-nums text-white/90">
+              {altFeet !== null ? altFeet.toLocaleString() : "—"}
+            </p>
+            <p className="text-[8px] font-medium text-white/25">ft</p>
+          </div>
+
+          <div className="flex min-w-11 flex-col items-center justify-center border-r border-white/6 px-2.5 py-1.5 sm:min-w-14 sm:px-2.5">
+            <div className="flex items-center gap-0.5 text-white/30">
+              <Gauge className="h-2 w-2" />
+              <span className="text-[8px] font-semibold uppercase tracking-wider">
+                SPD
+              </span>
+            </div>
+            <p className="text-[13px] font-bold tabular-nums text-white/90">
+              {speedKts ?? "—"}
+            </p>
+            <p className="text-[8px] font-medium text-white/25">kts</p>
+          </div>
+
+          <div className="flex min-w-12 flex-col items-center justify-center border-r border-white/6 px-2.5 py-1.5 sm:min-w-16 sm:px-2.5">
+            <div className="flex items-center gap-0.5 text-white/30">
+              {vsIcon ?? <Minus className="h-2 w-2" />}
+              <span className="text-[8px] font-semibold uppercase tracking-wider">
+                V/S
+              </span>
+            </div>
+            <p
+              className={`text-[13px] font-bold tabular-nums ${
+                vs !== null && vs > 0.5
+                  ? "text-emerald-400/80"
+                  : vs !== null && vs < -0.5
+                    ? "text-amber-400/80"
+                    : "text-white/90"
+              }`}
+            >
+              {vsDisplay ?? "—"}
+            </p>
+            <p className="text-[8px] font-medium text-white/25">fpm</p>
+          </div>
+
+          <button
+            onClick={onExit}
+            className="flex items-center gap-1 px-2.5 py-1.5 text-white/40 transition-colors hover:bg-white/5 hover:text-white/60 sm:px-2.5"
+            aria-label="Exit first person view"
+            title="Exit FPV (Esc)"
+          >
+            <X className="h-3.5 w-3.5" />
+          </button>
+        </div>
+      </div>
+    </motion.div>
+  );
+}

src/components/ui/keyboard-shortcuts-help.tsx

@@ -9,6 +9,7 @@ const SHORTCUTS = [
   { key: "R", description: "Reset view" },
   { key: "O", description: "Toggle orbit" },
   { key: "/", description: "Open search" },
+  { key: "F", description: "First person view" },
   { key: "?", description: "Shortcuts help" },
   { key: "Esc", description: "Close / Deselect" },
 ] as const;

src/components/ui/map-attribution.tsx

@@ -11,18 +11,17 @@ type MapAttributionProps = {
 
 const SM_BREAKPOINT = 640;
 
-function getInitialExpanded(): boolean {
-  if (typeof window === "undefined") return true;
-  return window.innerWidth >= SM_BREAKPOINT;
-}
-
 export function MapAttribution({ styleId }: MapAttributionProps) {
-  const [expanded, setExpanded] = useState(getInitialExpanded);
+  const [expanded, setExpanded] = useState(false);
   const attributions = getAttributions(styleId);
   const containerRef = useRef<HTMLDivElement>(null);
 
   const toggle = useCallback(() => setExpanded((prev) => !prev), []);
 
+  useEffect(() => {
+    setExpanded(window.innerWidth >= SM_BREAKPOINT);
+  }, []);
+
   // Close on outside click for small screens
   useEffect(() => {
     if (!expanded) return;

src/hooks/use-flights.ts

@@ -19,6 +19,7 @@ const CREDIT_TIER_EMERGENCY = 200;
 
 const RATE_LIMIT_BACKOFF_MS = 30_000;
 const VISIBILITY_RESUME_STALE_MS = 60_000;
+const FPV_BBOX_RADIUS = 2;
 
 function adaptiveInterval(creditsRemaining: number | null): number {
   if (creditsRemaining === null) return BASE_POLL_MS;
@@ -28,7 +29,15 @@ function adaptiveInterval(creditsRemaining: number | null): number {
   return BASE_POLL_MS;
 }
 
-export function useFlights(city: City | null) {
+/**
+ * Fetches flights via OpenSky. In FPV mode the bbox moves with the tracked
+ * aircraft (4×4° = 1 API credit). City changes are ignored while in FPV.
+ */
+export function useFlights(
+  city: City | null,
+  fpvIcao24: string | null = null,
+  fpvSeedCenter: { lng: number; lat: number } | null = null,
+) {
   const [flights, setFlights] = useState<FlightState[]>([]);
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -42,6 +51,32 @@ export function useFlights(city: City | null) {
 
   const creditsRef = useRef<number | null>(null);
   const lastFetchRef = useRef(0);
+  const fpvCenterRef = useRef<{ lng: number; lat: number } | null>(null);
+  const fpvSeedCenterRef = useRef<{ lng: number; lat: number } | null>(
+    fpvSeedCenter,
+  );
+  const fpvIcao24Ref = useRef<string | null>(fpvIcao24);
+  const fpvSeedRef = useRef<string | null>(null);
+  const fetchDataRef = useRef<(target: City) => void>(() => {});
+  fpvIcao24Ref.current = fpvIcao24;
+  fpvSeedCenterRef.current = fpvSeedCenter;
+
+  useEffect(() => {
+    if (!fpvIcao24) {
+      fpvCenterRef.current = null;
+      fpvSeedRef.current = null;
+      return;
+    }
+    if (fpvSeedRef.current === fpvIcao24) return;
+
+    const match = flights.find(
+      (f) => f.icao24.toLowerCase() === fpvIcao24,
+    );
+    if (match?.longitude != null && match?.latitude != null) {
+      fpvCenterRef.current = { lng: match.longitude, lat: match.latitude };
+    }
+    fpvSeedRef.current = fpvIcao24;
+  }, [fpvIcao24, flights]);
 
   const clearCountdown = useCallback(() => {
     if (countdownRef.current) {
@@ -75,10 +110,11 @@ export function useFlights(city: City | null) {
   const scheduleNext = useCallback(
     (target: City, delayMs: number) => {
       clearSchedule();
-      timerRef.current = setTimeout(() => fetchData(target), delayMs);
+      timerRef.current = setTimeout(() => {
+        fetchDataRef.current(target);
+      }, delayMs);
     },
-    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [clearSchedule],
-    [],
   );
 
   const fetchData = useCallback(
@@ -90,18 +126,50 @@ export function useFlights(city: City | null) {
       try {
         setLoading(true);
         setError(null);
+        let bbox: [number, number, number, number];
+        const inFpv = fpvIcao24Ref.current !== null;
+
+        if (inFpv && fpvCenterRef.current) {
+          bbox = bboxFromCenter(
+            fpvCenterRef.current.lng,
+            fpvCenterRef.current.lat,
+            FPV_BBOX_RADIUS,
+          );
+        } else if (inFpv && fpvSeedCenterRef.current) {
+          fpvCenterRef.current = fpvSeedCenterRef.current;
+          bbox = bboxFromCenter(
+            fpvSeedCenterRef.current.lng,
+            fpvSeedCenterRef.current.lat,
+            FPV_BBOX_RADIUS,
+          );
+        } else if (inFpv) {
+          fpvCenterRef.current = {
+            lng: target.coordinates[0],
+            lat: target.coordinates[1],
+          };
+          bbox = bboxFromCenter(
+            target.coordinates[0],
+            target.coordinates[1],
+            FPV_BBOX_RADIUS,
+          );
+        } else {
+          bbox = bboxFromCenter(
+            target.coordinates[0],
+            target.coordinates[1],
+            target.radius,
+          );
+        }
 
-        const bbox = bboxFromCenter(
-          target.coordinates[0],
-          target.coordinates[1],
-          target.radius,
-        );
         const result = await fetchFlightsByBbox(...bbox, controller.signal);
 
         if (result.rateLimited) {
+          const retryDelayMs =
+            result.retryAfterSeconds && result.retryAfterSeconds > 0
+              ? result.retryAfterSeconds * 1000
+              : RATE_LIMIT_BACKOFF_MS;
           setRateLimited(true);
-          startCountdown(RATE_LIMIT_BACKOFF_MS);
+          startCountdown(retryDelayMs);
-          scheduleNext(target, RATE_LIMIT_BACKOFF_MS);
+          scheduleNext(target, retryDelayMs);
           return;
         }
 
@@ -109,6 +177,17 @@ export function useFlights(city: City | null) {
         clearCountdown();
         setFlights(result.flights);
         lastFetchRef.current = Date.now();
+        if (inFpv && fpvIcao24Ref.current) {
+          const tracked = result.flights.find(
+            (f) => f.icao24.toLowerCase() === fpvIcao24Ref.current,
+          );
+          if (tracked?.longitude != null && tracked?.latitude != null) {
+            fpvCenterRef.current = {
+              lng: tracked.longitude,
+              lat: tracked.latitude,
+            };
+          }
+        }
 
         if (result.creditsRemaining !== null) {
           creditsRef.current = result.creditsRemaining;
@@ -121,7 +200,6 @@ export function useFlights(city: City | null) {
         const isAbort = err instanceof Error && err.name === "AbortError";
         if (isAbort) return;
         setError(err instanceof Error ? err.message : "Unknown error");
-        setFlights([]);
         scheduleNext(target, RATE_LIMIT_BACKOFF_MS);
       } finally {
         setLoading(false);
@@ -130,26 +208,30 @@ export function useFlights(city: City | null) {
     [scheduleNext, startCountdown, clearCountdown],
   );
 
+  useEffect(() => {
+    fetchDataRef.current = (target: City) => {
+      void fetchData(target);
+    };
+  }, [fetchData]);
+
   useEffect(() => {
     if (!city) return;
 
     const activeCity = city;
 
     function onVisibilityChange() {
-      if (document.visibilityState === "visible") {
+      if (document.visibilityState !== "visible") return;
-        const elapsed = Date.now() - lastFetchRef.current;
 
-        if (elapsed >= VISIBILITY_RESUME_STALE_MS) {
+      const elapsed = Date.now() - lastFetchRef.current;
-          clearSchedule();
+
-          fetchData(activeCity);
+      if (elapsed >= VISIBILITY_RESUME_STALE_MS) {
-        } else {
-          const interval = adaptiveInterval(creditsRef.current);
-          const remaining = Math.max(1_000, interval - elapsed);
-          clearSchedule();
-          scheduleNext(activeCity, remaining);
-        }
-      } else {
         clearSchedule();
+        fetchData(activeCity);
+      } else {
+        const interval = adaptiveInterval(creditsRef.current);
+        const remaining = Math.max(1_000, interval - elapsed);
+        clearSchedule();
+        scheduleNext(activeCity, remaining);
       }
     }
 
@@ -160,6 +242,8 @@ export function useFlights(city: City | null) {
   }, [city, fetchData, scheduleNext, clearSchedule]);
 
   useEffect(() => {
+    if (fpvIcao24Ref.current !== null) return;
+
     clearSchedule();
 
     if (!city) {
@@ -182,5 +266,29 @@ export function useFlights(city: City | null) {
     };
   }, [city, fetchData, clearCountdown, clearSchedule]);
 
+  const prevFpvRef = useRef<string | null>(fpvIcao24);
+  useEffect(() => {
+    const wasInFpv = prevFpvRef.current !== null;
+    const isInFpv = fpvIcao24 !== null;
+    prevFpvRef.current = fpvIcao24;
+
+    if (!wasInFpv && isInFpv) {
+      clearSchedule();
+      if (city) fetchData(city);
+    } else if (wasInFpv && !isInFpv && city) {
+      fpvCenterRef.current = null;
+      clearSchedule();
+      fetchData(city);
+    }
+  }, [fpvIcao24, city, clearSchedule, fetchData]);
+
+  useEffect(() => {
+    return () => {
+      clearSchedule();
+      abortRef.current?.abort();
+      clearCountdown();
+    };
+  }, [clearSchedule, clearCountdown]);
+
   return { flights, loading, error, rateLimited, retryIn, creditsRemaining };
 }

src/hooks/use-keyboard-shortcuts.ts

@@ -9,6 +9,8 @@ type ShortcutActions = {
   onOpenSearch: () => void;
   onToggleHelp: () => void;
   onDeselect: () => void;
+  onToggleFpv: () => void;
+  isFpv?: boolean;
 };
 
 const INPUT_TAGS = new Set(["INPUT", "TEXTAREA", "SELECT"]);
@@ -40,6 +42,14 @@ export function useKeyboardShortcuts(actions: ShortcutActions) {
 
       if (dialogOpen) return;
 
+      if (a.isFpv) {
+        if (e.key === "f" || e.key === "F") {
+          e.preventDefault();
+          a.onToggleFpv();
+        }
+        return;
+      }
+
       switch (e.key) {
         case "n":
         case "N":
@@ -60,6 +70,11 @@ export function useKeyboardShortcuts(actions: ShortcutActions) {
           e.preventDefault();
           a.onOpenSearch();
           break;
+        case "f":
+        case "F":
+          e.preventDefault();
+          a.onToggleFpv();
+          break;
         case "?":
           e.preventDefault();
           a.onToggleHelp();

src/hooks/use-settings.tsx

@@ -22,12 +22,15 @@ export type Settings = {
   trailDistance: number;
   showShadows: boolean;
   showAltitudeColors: boolean;
+  fpvChaseDistance: number;
 };
 
 const TRAIL_THICKNESS_MIN = 1;
 const TRAIL_THICKNESS_MAX = 8;
 const TRAIL_DISTANCE_MIN = 12;
 const TRAIL_DISTANCE_MAX = 100;
+const FPV_CHASE_DISTANCE_MIN = 0.003;
+const FPV_CHASE_DISTANCE_MAX = 0.01;
 
 function clamp(value: number, min: number, max: number): number {
   return Math.max(min, Math.min(max, value));
@@ -45,6 +48,11 @@ function normalizeSettings(input: Settings): Settings {
     trailDistance: Math.round(
       clamp(input.trailDistance, TRAIL_DISTANCE_MIN, TRAIL_DISTANCE_MAX),
     ),
+    fpvChaseDistance: clamp(
+      input.fpvChaseDistance,
+      FPV_CHASE_DISTANCE_MIN,
+      FPV_CHASE_DISTANCE_MAX,
+    ),
   };
 }
 
@@ -57,6 +65,7 @@ const DEFAULT_SETTINGS: Settings = {
   trailDistance: 40,
   showShadows: true,
   showAltitudeColors: true,
+  fpvChaseDistance: 0.0048,
 };
 
 const STORAGE_KEY = "aeris:settings";
@@ -68,7 +77,6 @@ type StorageEnvelope = {
   data: Settings;
 };
 
-/** Validate that a parsed value matches the Settings shape. */
 function isValidSettings(obj: unknown): obj is Settings {
   if (typeof obj !== "object" || obj === null) return false;
   const s = obj as Record<string, unknown>;
@@ -87,7 +95,11 @@ function isValidSettings(obj: unknown): obj is Settings {
     s.trailDistance >= TRAIL_DISTANCE_MIN &&
     s.trailDistance <= TRAIL_DISTANCE_MAX &&
     typeof s.showShadows === "boolean" &&
-    typeof s.showAltitudeColors === "boolean"
+    typeof s.showAltitudeColors === "boolean" &&
+    typeof s.fpvChaseDistance === "number" &&
+    Number.isFinite(s.fpvChaseDistance) &&
+    s.fpvChaseDistance >= FPV_CHASE_DISTANCE_MIN &&
+    s.fpvChaseDistance <= FPV_CHASE_DISTANCE_MAX
   );
 }
 
@@ -121,7 +133,7 @@ function saveSettings(settings: Settings): void {
     const envelope: StorageEnvelope = { v: STORAGE_VERSION, data: settings };
     localStorage.setItem(STORAGE_KEY, JSON.stringify(envelope));
   } catch {
-    /* quota exceeded or blocked */
+    /* noop */
   }
 }
 

src/lib/airports.ts

@@ -72607,3 +72607,24 @@ export function airportToCity(airport: Airport): City {
     radius: DEFAULT_RADIUS,
   };
 }
+
+/**
+ * Returns a subset of major airports (those with 3-letter IATA codes that are
+ * in the CITIES list or have well-known IATA codes). Useful for route inference
+ * where searching all 72K airports would be too slow.
+ *
+ * Cached after first call.
+ */
+let _majorAirportsCache: Airport[] | null = null;
+
+export function getMajorAirports(): Airport[] {
+  if (_majorAirportsCache) return _majorAirportsCache;
+
+  // All airports with a 3-letter IATA code (major airports tend to have them)
+  // Filter to those whose IATA is alpha-only (excludes numeric/special codes)
+  const alphaIata = /^[A-Z]{3}$/;
+  _majorAirportsCache = AIRPORTS.filter(
+    (a) => a.iata && alphaIata.test(a.iata.toUpperCase()),
+  );
+  return _majorAirportsCache;
+}

src/lib/flight-utils.ts

@@ -26,7 +26,7 @@ function lerpColor(a: RGB, b: RGB, t: number): RGB {
 export function altitudeToColor(
   altitude: number | null,
 ): [number, number, number, number] {
-  if (altitude === null) return [100, 100, 100, 200];
+  if (altitude === null || !Number.isFinite(altitude)) return [100, 100, 100, 200];
 
   const normalized = Math.min(Math.max(altitude / MAX_ALTITUDE_METERS, 0), 1);
   const t = Math.pow(normalized, 0.4);
@@ -46,17 +46,17 @@ export function altitudeToColor(
 }
 
 export function altitudeToElevation(altitude: number | null): number {
-  if (altitude === null) return 0;
+  if (altitude === null || !Number.isFinite(altitude)) return 0;
   return Math.max(altitude * 5, 200);
 }
 
 export function metersToFeet(meters: number | null): string {
-  if (meters === null) return "—";
+  if (meters === null || !Number.isFinite(meters)) return "—";
   return `${Math.round(meters * 3.28084).toLocaleString()} ft`;
 }
 
 export function msToKnots(ms: number | null): string {
-  if (ms === null) return "—";
+  if (ms === null || !Number.isFinite(ms)) return "—";
   return `${Math.round(ms * 1.94384)} kts`;
 }
 
@@ -66,8 +66,8 @@ export function formatCallsign(callsign: string | null): string {
 }
 
 export function headingToCardinal(degrees: number | null): string {
-  if (degrees === null) return "—";
+  if (degrees === null || !Number.isFinite(degrees)) return "—";
   const directions = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
-  const index = Math.round(degrees / 45) % 8;
+  const index = ((Math.round(degrees / 45) % 8) + 8) % 8;
   return directions[index];
 }

src/lib/opensky.ts

@@ -2,6 +2,8 @@
 
 const OPENSKY_API = "https://opensky-network.org/api";
 const FETCH_TIMEOUT_MS = 15_000;
+const ICAO24_REGEX = /^[0-9a-f]{6}$/i;
+const CALLSIGN_CACHE_TTL_MS = 30_000;
 
 export type FlightState = {
   icao24: string;
@@ -26,45 +28,114 @@ type OpenSkyResponse = {
   states: (string | number | boolean | null)[][] | null;
 };
 
-function parseStates(raw: OpenSkyResponse): FlightState[] {
+type ParseStateOptions = {
-  if (!raw.states) return [];
+  includeGround?: boolean;
+  requireBaroAltitude?: boolean;
+};
+
+type RateLimitInfo = {
+  creditsRemaining: number | null;
+  retryAfterSeconds: number | null;
+};
+
+const clamp = (value: number, min: number, max: number) =>
+  Math.min(Math.max(value, min), max);
+
+function parseIntegerHeader(value: string | null): number | null {
+  if (value === null) return null;
+  const parsed = Number.parseInt(value, 10);
+  return Number.isFinite(parsed) ? parsed : null;
+}
+
+function parseRateLimitInfo(response: Response): RateLimitInfo {
+  return {
+    creditsRemaining: parseIntegerHeader(
+      response.headers.get("x-rate-limit-remaining"),
+    ),
+    retryAfterSeconds: parseIntegerHeader(
+      response.headers.get("x-rate-limit-retry-after-seconds"),
+    ),
+  };
+}
+
+function isFiniteNumber(value: unknown): value is number {
+  return typeof value === "number" && Number.isFinite(value);
+}
+
+function normalizeBounds(
+  lower: number,
+  upper: number,
+  min: number,
+  max: number,
+): [number, number] {
+  if (!Number.isFinite(lower) || !Number.isFinite(upper)) {
+    throw new Error("Invalid bounding box coordinates");
+  }
+  const lo = clamp(lower, min, max);
+  const hi = clamp(upper, min, max);
+  return lo <= hi ? [lo, hi] : [hi, lo];
+}
+
+function parseStateRow(rawState: (string | number | boolean | null)[]): FlightState | null {
+  if (rawState.length < 17) return null;
+
+  const icao24 = typeof rawState[0] === "string" ? rawState[0].toLowerCase() : "";
+  if (!ICAO24_REGEX.test(icao24)) return null;
+
+  const longitude = isFiniteNumber(rawState[5]) ? rawState[5] : null;
+  const latitude = isFiniteNumber(rawState[6]) ? rawState[6] : null;
+  const baroAltitude = isFiniteNumber(rawState[7]) ? rawState[7] : null;
+
+  return {
+    icao24,
+    callsign: typeof rawState[1] === "string" ? rawState[1].trim() || null : null,
+    originCountry:
+      typeof rawState[2] === "string" ? rawState[2] : "Unknown",
+    longitude,
+    latitude,
+    baroAltitude,
+    onGround: rawState[8] === true,
+    velocity: isFiniteNumber(rawState[9]) ? rawState[9] : null,
+    trueTrack: isFiniteNumber(rawState[10]) ? rawState[10] : null,
+    verticalRate: isFiniteNumber(rawState[11]) ? rawState[11] : null,
+    geoAltitude: isFiniteNumber(rawState[13]) ? rawState[13] : null,
+    squawk: typeof rawState[14] === "string" ? rawState[14] : null,
+    spiFlag: rawState[15] === true,
+    positionSource: isFiniteNumber(rawState[16]) ? rawState[16] : 0,
+    category: isFiniteNumber(rawState[17]) ? rawState[17] : null,
+  };
+}
+
+function parseStates(raw: OpenSkyResponse, options?: ParseStateOptions): FlightState[] {
+  if (!raw || !Array.isArray(raw.states)) return [];
+
+  const includeGround = options?.includeGround ?? false;
+  const requireBaroAltitude = options?.requireBaroAltitude ?? true;
 
   return raw.states
-    .map((s) => ({
+    .map(parseStateRow)
-      icao24: s[0] as string,
+    .filter((state): state is FlightState => state !== null)
-      callsign: (s[1] as string)?.trim() || null,
-      originCountry: s[2] as string,
-      longitude: s[5] as number | null,
-      latitude: s[6] as number | null,
-      baroAltitude: s[7] as number | null,
-      onGround: s[8] as boolean,
-      velocity: s[9] as number | null,
-      trueTrack: s[10] as number | null,
-      verticalRate: s[11] as number | null,
-      geoAltitude: s[13] as number | null,
-      squawk: s[14] as string | null,
-      spiFlag: s[15] as boolean,
-      positionSource: s[16] as number,
-      category: (s[17] as number | null) ?? null,
-    }))
     .filter(
       (f) =>
         f.longitude !== null &&
         f.latitude !== null &&
-        !f.onGround &&
+        (includeGround || !f.onGround) &&
-        f.baroAltitude !== null,
+        (!requireBaroAltitude || f.baroAltitude !== null),
     );
 }
 
+function normalizeCallsign(value: string | null): string {
+  if (!value) return "";
+  return value.trim().toUpperCase().replace(/\s+/g, "");
+}
+
 export type FetchResult = {
   flights: FlightState[];
   rateLimited: boolean;
   creditsRemaining: number | null;
+  retryAfterSeconds: number | null;
 };
 
-const clamp = (v: number, lo: number, hi: number) =>
-  Math.min(Math.max(v, lo), hi);
-
 export async function fetchFlightsByBbox(
   lamin: number,
   lamax: number,
@@ -72,10 +143,8 @@ export async function fetchFlightsByBbox(
   lomax: number,
   signal?: AbortSignal,
 ): Promise<FetchResult> {
-  const la0 = clamp(lamin, -90, 90);
+  const [la0, la1] = normalizeBounds(lamin, lamax, -90, 90);
-  const la1 = clamp(lamax, -90, 90);
+  const [lo0, lo1] = normalizeBounds(lomin, lomax, -180, 180);
-  const lo0 = clamp(lomin, -180, 180);
-  const lo1 = clamp(lomax, -180, 180);
 
   const url = `${OPENSKY_API}/states/all?lamin=${la0}&lamax=${la1}&lomin=${lo0}&lomax=${lo1}&extended=1`;
 
@@ -89,26 +158,37 @@ export async function fetchFlightsByBbox(
       cache: "no-store",
       signal: controller.signal,
     });
+    const rateLimitInfo = parseRateLimitInfo(res);
 
     if (res.status === 429) {
-      return { flights: [], rateLimited: true, creditsRemaining: null };
+      return {
+        flights: [],
+        rateLimited: true,
+        creditsRemaining: rateLimitInfo.creditsRemaining,
+        retryAfterSeconds: rateLimitInfo.retryAfterSeconds,
+      };
     }
 
     if (!res.ok) {
-      return { flights: [], rateLimited: false, creditsRemaining: null };
+      return {
+        flights: [],
+        rateLimited: false,
+        creditsRemaining: rateLimitInfo.creditsRemaining,
+        retryAfterSeconds: null,
+      };
     }
 
-    const data: OpenSkyResponse = await res.json();
+    const payload = (await res.json()) as unknown;
-    const creditsRaw = res.headers.get("x-rate-limit-remaining");
+    const data =
-    const creditsRemaining =
+      typeof payload === "object" && payload !== null
-      creditsRaw !== null ? parseInt(creditsRaw, 10) : null;
+        ? (payload as OpenSkyResponse)
+        : { time: 0, states: null };
 
     return {
       flights: parseStates(data),
       rateLimited: false,
-      creditsRemaining: Number.isNaN(creditsRemaining)
+      creditsRemaining: rateLimitInfo.creditsRemaining,
-        ? null
+      retryAfterSeconds: null,
-        : creditsRemaining,
     };
   } catch (err) {
     if (err instanceof Error && err.name === "AbortError") {
@@ -129,3 +209,251 @@ export function bboxFromCenter(
 ): [lamin: number, lamax: number, lomin: number, lomax: number] {
   return [lat - radiusDeg, lat + radiusDeg, lng - radiusDeg, lng + radiusDeg];
 }
+
+/**
+ * Fetch a single aircraft's state by its ICAO24 address (global lookup).
+ * Costs 4 API credits (no bbox = full globe) but returns at most one result.
+ * Returns the flight if found, or null.
+ */
+export async function fetchFlightByIcao24(
+  icao24: string,
+  signal?: AbortSignal,
+): Promise<{ flight: FlightState | null; creditsRemaining: number | null }> {
+  const normalizedIcao24 = icao24.trim().toLowerCase();
+  if (!ICAO24_REGEX.test(normalizedIcao24)) {
+    return { flight: null, creditsRemaining: null };
+  }
+
+  const url = `${OPENSKY_API}/states/all?icao24=${encodeURIComponent(normalizedIcao24)}&extended=1`;
+
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
+  const onExternalAbort = () => controller.abort();
+  signal?.addEventListener("abort", onExternalAbort);
+
+  try {
+    const res = await fetch(url, {
+      cache: "no-store",
+      signal: controller.signal,
+    });
+    const rateLimitInfo = parseRateLimitInfo(res);
+
+    if (res.status === 429 || !res.ok) {
+      return { flight: null, creditsRemaining: rateLimitInfo.creditsRemaining };
+    }
+
+    const payload = (await res.json()) as unknown;
+    const data =
+      typeof payload === "object" && payload !== null
+        ? (payload as OpenSkyResponse)
+        : { time: 0, states: null };
+    const flights = parseStates(data, {
+      includeGround: true,
+      requireBaroAltitude: false,
+    });
+    return {
+      flight:
+        flights.find((f) => f.icao24 === normalizedIcao24) ?? null,
+      creditsRemaining: rateLimitInfo.creditsRemaining,
+    };
+  } catch (err) {
+    if (err instanceof Error && err.name === "AbortError") {
+      if (signal?.aborted) throw err;
+    }
+    return { flight: null, creditsRemaining: null };
+  } finally {
+    clearTimeout(timer);
+    signal?.removeEventListener("abort", onExternalAbort);
+  }
+}
+
+type CallsignLookupResult = {
+  flight: FlightState | null;
+  creditsRemaining: number | null;
+  rateLimited: boolean;
+  retryAfterSeconds: number | null;
+};
+
+const callsignLookupCache = new Map<
+  string,
+  { timestamp: number; result: CallsignLookupResult }
+>();
+
+export async function fetchFlightByCallsign(
+  callsign: string,
+  signal?: AbortSignal,
+): Promise<CallsignLookupResult> {
+  const normalizedQuery = normalizeCallsign(callsign);
+  if (!normalizedQuery) {
+    return {
+      flight: null,
+      creditsRemaining: null,
+      rateLimited: false,
+      retryAfterSeconds: null,
+    };
+  }
+
+  const cached = callsignLookupCache.get(normalizedQuery);
+  if (cached && Date.now() - cached.timestamp <= CALLSIGN_CACHE_TTL_MS) {
+    return cached.result;
+  }
+
+  const url = `${OPENSKY_API}/states/all?extended=1`;
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
+  const onExternalAbort = () => controller.abort();
+  signal?.addEventListener("abort", onExternalAbort);
+
+  try {
+    const res = await fetch(url, {
+      cache: "no-store",
+      signal: controller.signal,
+    });
+    const rateLimitInfo = parseRateLimitInfo(res);
+
+    if (res.status === 429) {
+      return {
+        flight: null,
+        creditsRemaining: rateLimitInfo.creditsRemaining,
+        rateLimited: true,
+        retryAfterSeconds: rateLimitInfo.retryAfterSeconds,
+      };
+    }
+
+    if (!res.ok) {
+      return {
+        flight: null,
+        creditsRemaining: rateLimitInfo.creditsRemaining,
+        rateLimited: false,
+        retryAfterSeconds: null,
+      };
+    }
+
+    const payload = (await res.json()) as unknown;
+    const data =
+      typeof payload === "object" && payload !== null
+        ? (payload as OpenSkyResponse)
+        : { time: 0, states: null };
+
+    const flights = parseStates(data, {
+      includeGround: true,
+      requireBaroAltitude: false,
+    });
+
+    const exact = flights.find(
+      (f) => normalizeCallsign(f.callsign) === normalizedQuery,
+    );
+    const startsWith =
+      exact ??
+      flights.find((f) => normalizeCallsign(f.callsign).startsWith(normalizedQuery));
+    const contains =
+      startsWith ??
+      flights.find((f) => normalizeCallsign(f.callsign).includes(normalizedQuery));
+
+    const result: CallsignLookupResult = {
+      flight: contains ?? null,
+      creditsRemaining: rateLimitInfo.creditsRemaining,
+      rateLimited: false,
+      retryAfterSeconds: null,
+    };
+
+    callsignLookupCache.set(normalizedQuery, {
+      timestamp: Date.now(),
+      result,
+    });
+
+    return result;
+  } catch (err) {
+    if (err instanceof Error && err.name === "AbortError") {
+      if (signal?.aborted) throw err;
+    }
+    return {
+      flight: null,
+      creditsRemaining: null,
+      rateLimited: false,
+      retryAfterSeconds: null,
+    };
+  } finally {
+    clearTimeout(timer);
+    signal?.removeEventListener("abort", onExternalAbort);
+  }
+}
+
+const SEGMENT_DELAY_MS = 200;
+
+/**
+ * Fetch flights across multiple bounding-box segments (for route corridors).
+ * Segments are fetched sequentially with a small delay to avoid burst rate limits.
+ * Results are merged and deduplicated by icao24.
+ *
+ * If a 429 is received mid-sequence, partial results collected so far are returned
+ * with `rateLimited: true`.
+ */
+export async function fetchFlightsByRoute(
+  segments: { lamin: number; lamax: number; lomin: number; lomax: number }[],
+  signal?: AbortSignal,
+): Promise<FetchResult> {
+  if (segments.length === 0) {
+    return {
+      flights: [],
+      rateLimited: false,
+      creditsRemaining: null,
+      retryAfterSeconds: null,
+    };
+  }
+
+  const seen = new Map<string, FlightState>();
+  let rateLimited = false;
+  let lowestCredits: number | null = null;
+  let retryAfterSeconds: number | null = null;
+
+  for (let i = 0; i < segments.length; i++) {
+    if (signal?.aborted) throw new DOMException("Aborted", "AbortError");
+
+    const seg = segments[i];
+    const result = await fetchFlightsByBbox(
+      seg.lamin,
+      seg.lamax,
+      seg.lomin,
+      seg.lomax,
+      signal,
+    );
+
+    for (const f of result.flights) {
+      if (!seen.has(f.icao24)) {
+        seen.set(f.icao24, f);
+      }
+    }
+
+    if (result.creditsRemaining !== null) {
+      lowestCredits =
+        lowestCredits === null
+          ? result.creditsRemaining
+          : Math.min(lowestCredits, result.creditsRemaining);
+    }
+
+    if (result.rateLimited) {
+      rateLimited = true;
+      retryAfterSeconds = result.retryAfterSeconds;
+      break;
+    }
+
+    if (i < segments.length - 1) {
+      await new Promise<void>((resolve) => {
+        const timer = setTimeout(resolve, SEGMENT_DELAY_MS);
+        const onAbort = () => {
+          clearTimeout(timer);
+          resolve();
+        };
+        signal?.addEventListener("abort", onAbort, { once: true });
+      });
+    }
+  }
+
+  return {
+    flights: Array.from(seen.values()),
+    rateLimited,
+    creditsRemaining: lowestCredits,
+    retryAfterSeconds,
+  };
+}