I've just been thinking about this.. It's like walking on a treadmill, you're walking the same speed as the belt is moving, but you're not going anywhere, you're in the same place. If it was like this with the plane, it'd work the same as if the engines etc were all at full blast, but with the plane on the spot. If my understanding of how planes work is right, then it wouldn't take off, because there's no air being blasted under the wings, making it fly. - Well, not enough anyway? If the plane was actually moving along the conveyor, say 100mph. Then surely this would be the same as it going 100mph normally? If it couldn't take off at 100mph normally, then what would make it take off at 100mph on a conveyor? - The only difference, is the wheels moving twice the normal speed. I'm pretty sure the wheel's don't control the drive of the plane, they just sit freely, like our front wheels do. They just get pushed along by the drivechain. Thought i'd post this, just for fun. - http://video.google.co.uk/videoplay?docid=...amp;q=treadmill