Ignoring the safety concern on one side, and the emission of greenhouse gases on the other, the way this works is interesting and surprisingly straightforward!

Ignoring the safety concern on one side, and the emission of greenhouse gases on the other, the way this works is interesting and surprisingly straightforward! https://github.com/Jxck-S/plane-notify/blob/multi/PseudoCode.md https://github.com/Jxck-S/plane-notify/blob/multi/PseudoCode... If I understand correctly, the plane broadcasts ACARS data which include the registration number, and ADS-B data which includes the 24-bit ICAO address, which hobbyists both record and share in an API that can be queried. Then the code computes departures and arrivals from the distance to the nearest airport at low altitude. The jet likely changed its ICAO address through PIA, but the set of possible ICAO addresses that could be the right one after it switched ICAO address is small, because the switch happened at a known airport, and because PIA privacy protection has an assigned range of registration numbers and ICAO addresses. Among those, there was only one that matched the departure/arrival pattern of the pre-PIA, known ICAO address associated with the target jet.