by Travis » Tue May 19, 2009 2:20 pm
I've never added this to one of my own aircraft, since tail numbers come in all sorts of colors and sizes, sometimes on different areas of the aircraft.
But from what I remember, you need to create a small plane on the outer hull, and give it a specific name. That will then become the "tail number" and whatever is in the "atc_id=" slot in the aircraft.cfg will be what is printed on the side.