If you happened to be in a place with no domestic flight, I assume the game is not able to move on because custom checkpoint hasn’t been unlocked yet, am I right?
You could build your GA stands, a small terminal where you can employ some administrators and while the GA earns you money, research what you need
Cool. I’ll try that. Thanks. XD
Update: I doubt there’s a research that is going to solve that.
Are you asking if the game in its default settings can handle an airport placed in a country where there are no other airports? Which area are you placing your airport in?