The conveyor belt is an irrelevant factor in the whole equation. The only thing that happens is the wheels will be spinning twice as fast in relation to a predetermined runway speed. With this said, the wheels have nothing to do with lift. What creates lift is the resistance of some type of medium (air or liquid) against a wing and/or rudder. Submarines use wings & rudders to move up/down/left/right through the water just like aircraft in the air; we'll leave bouyancy control of this for simplicity's sake. For aircraft, they need a certain amount of speed through the air to create a particular amount of wind resistance against their wings to get their weight off the ground. Keep in mind that wing size, shape, and design can affect the speed required for takeoff; not including payload.

The only way an aircraft will create lift while stationary is inside a wind-tunnel.