[MrL_JaKiri]

Originally Posted by 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.

No.

Originally Posted by MEEEEE

Strictly speaking, the problem is meaningless if you don't assume it can take off - because if you believe it makes it so the plane can't take off because the air is stationary around it, the speed of the plane is zero and thus the ground isn't moving. Of course, instantaneously, the plane has a speed relative to the air again, and so you get an infinitely fast progression.

The only sensible way of looking at it, if you want to consider what people think it means, is that if the ground has the same speed as the speed of the outer surface of the wheels.

Originally Posted by Tomkat

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.

You still don't appear to know how planes work, or how friction works, or both.