One of the best is https://airplanes.live/ - which currently aggregates data from nearly 1700 feeders globally; they have a legal agreement preventing sale of this data (to avoid situations like with adsbexchange); they share the data on a selective basis.
One of the largest ones, Opensky Network - is supposed to be open for research purposes but they refused my request straight ahead.
The list of all data exchanges is here: https://github.com/ClickHouse/adsb.exposed/?tab=readme-ov-fi...
One of the best is https://airplanes.live/ - which currently aggregates data from nearly 1700 feeders globally; they have a legal agreement preventing sale of this data (to avoid situations like with adsbexchange); they share the data on a selective basis.
One of the largest ones, Opensky Network - is supposed to be open for research purposes but they refused my request straight ahead.
https://adsb.lol/ - is controversial. This database is made available under the Open Database License: http://opendatacommons.org/licenses/odbl/1.0/ plus under CC0, but there is some drama that I don't understand: https://github.com/ClickHouse/adsb.exposed/issues/12#issueco...