How TripStow finds the exact plane you flew on

A flight number is a timetable slot: BA117 leaves Heathrow for New York every day, flown by whichever 777 or A350 is free. The aircraft itself has its own registration, painted on the tail. That is the plane you sat in, and it is what fills your Hangar: every individual aircraft you have flown on, with its age, a photo and the ones you have been on more than once.

Booking emails never say which plane it was. So for every past flight without one, TripStow goes looking.

Three places a tail number can come from

• Your own records. Some booking emails and most flight log imports (myFlightradar24, OpenFlights and others) already include it. Anything you type in yourself always wins: TripStow never overwrites it.
• US government records. The US Department of Transportation publishes every domestic flight of the big US airlines, with the tail number, back to 1987. US domestic flights are filled in from these for free.
• The adsb.lol archive. For everything else since February 2023, TripStow reads the open archive of aircraft broadcasts collected by adsb.lol and its community of volunteer receivers. With Pro, live flight data adds the plane on the day too.

What an aircraft broadcasts

Airliners send out their position several times a second (ADS-B), with a unique transponder code and, once airborne, a callsign: BAW117 for BA117, DLH418 for LH418. Volunteers around the world receive these with small antennas and share them. adsb.lol publishes each day as an archive: one track per aircraft, three to four gigabytes a day.

Every morning TripStow reads the days it needs, opens only the tracks of airlines our travellers flew that day, cuts each aircraft's day into separate flights, and matches each traveller's flight to one of them. The match gives the registration, and the registration gives the plane.

Why matching is harder than it sounds

Most flights match in one step: the right callsign, at the right time, from the right airport. The rest taught us a lot.

• Coverage is uneven. Receivers cluster in Europe and North America. At some big airports elsewhere the archive barely sees aircraft on the ground, so a plane is known only from its cruise, with no take-off or landing.
• A plane can land and leave again unseen. Seen at cruising height before and after, two flights look like one long flight with the first flight's callsign. TripStow now splits a track after any half hour unseen, and joins the pieces of one flight back together when they share a callsign across an ocean.
• Times in old records can be hours out; dates rarely are. So the exact callsign, seen once, on the booked local date, counts even when the time does not line up.
• Codeshares never appear under their own number. A flight sold as AI8644 is Lufthansa's LH418, and Lufthansa often flies with a coded callsign. TripStow learns which flight operates a codeshare first, then looks for that one.
• Airlines reuse callsigns with letters. A callsign like QTR10H can be a different flight from QR10. Seen with no airports, it only counts if the aircraft type matches the booking: an A330 is not the A380 on the ticket.
• Airlines swap planes. A 787 standing in for a booked 777 is normal and accepted. A widebody for a flight booked on a narrowbody, or another airline's plane for an airline's own flight, is refused.

When TripStow is not sure, it leaves the tail number blank rather than guess. Every rule is tested on real flights and checked against the archive before it goes live, and when the rules improve, every flight still without a plane is looked at again.

What we publish, and what we never do

The archive is shared under the Open Database Licence, so the table of matched aircraft legs TripStow derives from it is published on the open data page, as the licence asks. It lists aircraft, callsigns and times, never travellers. Your trips stay private: future trips are never public, and which flights you took is yours alone.

Thank you to everyone who runs a receiver and feeds adsb.lol: you are the reason a traveller can see the exact plane that took them to New York in 2023.

See your own Hangar

Forward your booking emails or import your flight history, and TripStow fills in the planes behind your flights. Tail numbers found this way show on Pro; the trips, map and stats are free.