Science Squabbling

Teenslain, this problem encourages a logical error, you quite probably - given the original question see a situation where the conveyor cancels any forward motion of the plane so the plane is stationary relative to the air, no airspeed = no lift. the fact is the conveyor is spinning the wheels but that is basically irrelevant for the plane because the wheels are not powered in takeoff, the plane takes off as normal in the opposite direction of the conveyor only when it's airspeed is sufficient. for this to happen the conveyor must long enough for normal takeoff ie as long as a runway and at takeoff the wheels simply spin twice as fast as usual.