There are three airplanes, on three separate runways, each of which has a conveyor belt. You are offered the chance to select an airplane. After you do so, as the engines start to fire up, the conveyor belt under one of the other airplanes is turned on, sending the airplane crashing into the terminal.
Monty Hall then comes on the loudspeaker and explains that both of the remaining airplanes' engines are working correctly, but the conveyor belt under one of them will be turned on, such that it moves at a speed equal to that of the airplane above it, in the opposite direction. He then offers anybody who wants to the opportunity to switch planes.
Should you switch?