There is no automated connection between any of the tables in either database.
That also means you should be careful to maintain referential integrity between tables whenever making changes. Such as NOT adding a flight for an aircraft that doesn't exist, or adding a flight for a session that doesn't exist, etc. Or even deleting an aircraft where flights exist for that aircraft. Without knowing how Radarbox copes with such failures of referential integrity, it's a very dangerous business.
Airnav have not implemented any database triggers to deal with any referential integrity issues that may arise from end-users making updates outside of Radarbox.
By contrast, the Basestation database (SBS1) has triggers in the database to deal with deletions, such as:
CREATE TRIGGER AircraftIDdeltrig
BEFORE DELETE
ON Aircraft
BEGIN DELETE FROM Flights WHERE AircraftID = OLD.AircraftID;END;