Check it out. The plane must have air flow over the wings to produce lift. When the plane takes of from a standing start it pushes itself along the ground to reach a speed with enough airflow over the wings to give it lift. If it is sitting on a treadmill that travels the opposite way, this leaves the plane sitting still. It possibly may have a little forward motion, but not enough to create lift.
Only if the brakes are on, or the wheels removed, etc etc etc....#4 for sure.......If the plane didn't appear there out of "magic" then it must've ROLLED there. If it didn't roll there what was used to put the conveyer under it...Will it fly? IF it is otherwise able to fly, it will. If it is unable to fly then this whole exercise is useless, come to think of it, it's useless anyway you look at it..........MP