You mean Mythbusters actually did the airplane-on-a-conveyor-belt thing?
Wait, the pilot didn't think it would fly? That's not very reassuring. Look, dude, the plane doesn't get its forward motion from the landing gear. The wheels don't drive the plane, OK? The propeller does. That's why they call it that. It propels the plane. The plane won't sit still just because it's sitting on a moving surface. I thought the Navy doped this out years ago before they spent so much money building aircraft carriers.
(While filming "Six Days, Seven Nights", Harrison Ford [who actually can fly a plane] had to explain this to the director, who wanted Ford to taxi around without starting the propeller. He's good but he's not that good. While you're at it, see about holding the tide back too. Let me know how that goes for you.)
The question I thought this was about, which I think probably still is a good question (and is probably what some people thought the stunt was actually about), is whether the propeller, all by itself, can move enough air over the wings to generate enough lift to fly the plane without actual forward motion. I'm reasonably sure the answer to that one is "heck, no", but wouldn't it be neat to be proven wrong?