[Tomkat]

I think the main problem we have here is that Mark is thinking about this in a realistic sense, in which case the treadmill could never possibly exert the exact same force back. In that case, yeah, the plane would probably eventually build up enough speed and power to pull off the treadmill, and have accumulated enough to be able to take off.

But in this hypothetical situation, the treadmill can move at an infinite speed, thus preventing the plane from moving anywhere, no matter how much force it exerts from its engines.