In recent years, I'm being terrorized by airplanes flying over here all the time at low height. For this reason, I'm trying to set up a little notification system to see if these are actually "official" aircraft, and if so, who owns them and when they fly over here. Basically, I want to be able to verify on my screen that yes, that loud noise from the sky is indeed an actual commercial (or at least "registered") aircraft, and not just my imagination or worse.
So, for this reason, I've been hunting for free flight data. That is, the current GPS coordinates for all active airplanes in the world. (Or at least around my area.)
Unsurprisingly, there's eight million companies/websites out there which provide this data, but want to get paid, or have annoying registration requirements.
Eventually, I found this: https://opensky-network.org/
I started reading its manual: https://opensky-network.org/apidoc/rest.html
And found out that they do allow unregistered people to fetch their data here: https://opensky-network.org/api/states/all
However, studying the output from that JSON blob, I notice that, currently, it only contains 2482 "states", a "state" apparently meaning an airplane in the sky. And only one out of all those is said to be from Sweden.
Does this really mean that only 2482 airplanes are in the sky right now in the entire world, and that only ONE airplane is in the sky over Sweden? Or does the origin country label ("Country name inferred from the ICAO 24-bit address.") mean from which country the airplane is "owned"/based? Or where it started from for the current flight?
Whatever it means, 2482 airplanes sounds a bit low to me. Could this really be accurate? And if so, if this website can give it away for free, how can the others charge so much money for it?