You must be kidding.
The idea is that the speed of the plane is to be MATCHED by the conveyor and not allow it to overtake it. The faster the plane tries to go, the conveyor matches its speed. That was not happening on the clip at all. The planes speed overcame the conveyor speed.
Prop air generated over the wings is not sufficient to generate enough lift. The plane must be moving.
Its the same as the ball being shot out of the gun moving in the opposite direction. If a car is going west @ 60mph and you shoot a ball out of the back of the car facing east. The ball just drops. Been proven.