track-planes-and-shipslisted

# Track Planes and Ships Aircraft and ships announce themselves over the air, and volunteers with cheap receivers write it all down. That gives you movement history for most civil traffic and, through registries, a path to ownership. The cost: the data is self-reported by the vehicle, so it is exactly as truthful as its operator chooses. The beginner error is chasing the wrong identifier — tail numbers, callsigns, vessel names and MMSIs all change, while ICAO hex codes and IMO numbers largely don't. Resolve to the durable identifier first and everything downstream survives a rename. ## Triage: which identifier do you have? | You have | Resolve to | Why | |---|---|---| | Tail number / registration (`N…`, `G-…`, `D-…`) | ICAO 24-bit hex | Registration is reassigned when the aircraft is sold or re-registered; hex follows the current registration but is what the trackers key on | | Flight number or callsign | The specific airframe for that leg | Callsigns are per-flight and get reused daily by different aircraft | | ICAO hex | Nothing — you're already there | The durable aircraft selector, as broadcast | | Vessel name | IMO number | Names change with sale and with evasion; the hull doesn't | | MMSI | IMO number | MMSI is a radio identity issued by the flag state and is reissued on reflag | | IMO number | Nothing — you're already there | Permanent for the life of the hull | | A photo of the vehicle | The visible identifier, then the above | Spotter photo archives index by regis