Sorry for the late reply. The tracks endpoint has been deactivated a while ago, it needs a complete overhaul as it wasn't working as intended. For most research purposes the flights endpoint should do!
Just a small complementary question: so for the moment it is not possible to retrieve the track that an aircraft followed during a given flight (retrieved using the other requests eg GET Flights)? Is there any estimate when this feature will be available again?
Is there a way of retrieving states for one aircraft over a time period - e.g. last 10 minutes, 1 hour etc..? I've been capturing states via polling every 5 minutes for an area, but would prefer to have more granularity in the data. From what I understand, the "flights" endpoint is only calculated daily.