BTW, I found yesterday, that if you have Pilot2ATC, then the AI planes from FSLTL are visible in the minimap in this app.
If you hover over these blue AI planes in the map with your cursor, you get the label I was asking for also. It is not really an in game option, but good enough if you want to know where the plane that is taxiing in front of you is going. Or where a plane came from etc.