[RJon]

https://www.flightradar24.com/how-it-works

Flightradar24 is a flight tracker that shows live air traffic from around the world. Flightradar24 combines data from several data sources including ADS-B, MLAT and radar data. The ADS-B, MLAT and radar data is aggregated together with schedule and flight status data from airlines and airports to create a unique flight tracking experience on www.flightradar24.com and in Flightradar24 apps.