The Flights by Aircraft API is regularly returning the value EGKR (Redhill airfield) instead of EGKK (London Gatwick Airport) e.g.
opensky-network.org/api/flights/aircraft...72400&end=1614445200
[{"icao24":"40653d","firstSeen":1614357561,"estDepartureAirport":"EGPH","lastSeen":1614361306,"estArrivalAirport":"EGKR","callsign":"EZY9016 ","estDepartureAirportHorizDistance":2655,"estDepartureAirportVertDistance":362,"estArrivalAirportHorizDistance":6603,"estArrivalAirportVertDistance":115,"departureAirportCandidatesCount":0,"arrivalAirportCandidatesCount":2}]
The plane ICAO24 code is: 40653d is an "Airbus A319-111" which it too big to land at EGKR.
However, EGKR and EGKK are only a few miles apart so could this be confusing your algorithm? Please let me know if there is anything I can do to help.
Thanks.
Richard.