Well.... I think that erlec should be awarded full championship points for his research. Good job.
With his concept, it follows that you could expand it by one dimension ... z (or rather, rFactor Y), and craft a non rendered track in the air, and have helecopters follow this 3d track surface..... such that helicopters no longer need fly only in 2D circles.
If you leave the 'fuel' on, they could come in for landings (..their pit stop). Can you set rF cars to stop for fuel only? If so, your 'helicopter' would not raise up on air jacks when it landed (next to an infield hospital). Of course, it would take off again too.
When you have this invisible 'track' surface outside of your track, a camera helicopter could be be terrain following in a way, and follow the cars around a track.
Probably still couldn't cross over the racetrack surface, but still.....
Again.... Great work, erlec
Edit... actually, would not matter which side of track you are on .... so long as your heli ai line does not cross your track's ai.
Edit2.. If the invisible track is dirt for a short section, it's 'rotor' (ani) could 'blow up dirt' as it 'takes off' (after pitting).
Edit3... Blimps, Banking, Biplanes skywriting = forced engine overheating .... etc.. etc..