Stowaway draws the sky that is genuinely over you right now, with every aircraft and satellite in it, and lets you click one and take its window seat.

Worth correcting at the outset, because it gets described wrong: this is not a map. There is no tile layer anywhere in it — no OpenStreetMap, no Mapbox, nothing served as imagery squares. The sky is rendered. A physically-based atmosphere, the sun and moon placed by ephemeris for this exact minute, some nine thousand stars each carrying its own real magnitude and colour, and volumetric clouds pushed along by your location’s actual 850 hPa wind. Matching the real cloud amount overhead is one toggle further.

The traffic is equally real. Aircraft come from the public ADS-B feed at airplanes.live, polled every five seconds within eighty nautical miles of you; between polls each one is dead-reckoned along its track and late corrections are eased in rather than snapped, so nothing teleports. Satellites are propagated by SGP4 from CelesTrak orbital elements, refreshed twice a day. Click a plane and you get callsign, airline, type, registration, altitude, vertical rate, ground speed, heading and range — plus a photograph of that exact airframe, photographer credited, pulled from Planespotters.

Then press RIDE ALONG. You choose a seat: left window, right window, the pilot’s view, or a belly camera, each placed from the real fuselage geometry of the type you boarded, so a 747’s window sits further outboard than a Cessna’s. A cabin loop plays underneath, picked by engine — jet, turboprop, piston, helicopter, spacecraft. Below runs photogrammetric 3D terrain when it loads, plain ground when it doesn’t. You can also start from the other end: type DL542 and it finds that flight anywhere on earth and boards you.

It is free, wants no account, ships no analytics, and has no backend of its own — a static page calling public APIs straight from your browser. Location is a prompt you may refuse; decline and the view keeps Seattle, or search a city, landmark or postal code instead.

The limits are mostly ADS-B’s. Coverage comes from volunteer ground receivers, so oceans and empty country thin out, and the app’s own line when the feed goes quiet is that the sky may look emptier than it is. Satellites are the station and bright-visual catalogues — about 180 objects, not the full orbital census. Origin and destination are the one thing the panel won’t tell you. And it needs WebGL 2: weak hardware gets routed to a simpler sky, and is told so.