[EricH]

Originally Posted by greencactus3

vtol is not allowed. the plane's thrust is angled down so the conveyor belt can't move in the opposite direction anymore. illegal move

I was thinking outside the box. And if the conveyor belt isn't supported well enough, it will move--downwards--until it can't stretch anymore--and then it won't move anymore.

If someone has a powered model airplane with landing gear (improvised or included), they should put it on a treadmill (in a big open area), run both, take a video, and post it here. I think that's the only sure way to answer the question.