Me and nakedjoose (the guy I normally play with) have done this 3 times. Twice to a heli, and once to a ground engineer who was about to rocket us, I had to bail out and pull out my gustav
Only managed to get back in the heli once while falling though
I've done it once, actually. It was luck. I was actually copilot, and my pilot bailed. I jumped out, rocketed the heli who was attacking us, and jumped back in.
Lol! I remember trying to do something like that before. Killed the enemy plane, but I didn't manage to make it back into my plane. Instead, I hit the plane and died. :\