So, where is the flight tracking data for 13000 flights gathered from? The API may be fast but is the flight tracking data that it returns actually reliable? Yes. The raw data the Flights Tracker API returns is collected through various sources including our trusted data partners in the sector, aviation authorities, as well as other official sources like international organizations and non-governmental organizations when available. This data is then aggregated and stored in our servers and presented to you via REST APIs in JSON formats which is the industry standard.

Accessing this API for flight location data is very easy by a single API key that you can get here. It comes with an API subscription and you may use the same one for as long as your subscription is active. Once you register, you do not have to authorize or unlock the key in any way as it comes in all ready-to-use. With the key, use the below endpoints and if necessary, use available filters to get the exact data you are looking for among 15000 flights:

Source: https://aviation-edge.com/how-can-i-check-flight-location-with-api/