Back in the original question, the plane doesn't move forward then the conveyor doesn't move at all. So it's relative. If the plane doesn't move then the conveyor doesn't move. If the plane moves forward THEN the conveyor will move backwards. They conveyor is directly proportional to the plane. Unless the plane is actually moving forward the conveyor is doing nothing, it's not moving. So the plane has to be moving forward for anything to happen. If the plane is moving forward then it can generate lift and thus fly to New York.