[Rob WS6]

I just came to a realization... this is in a way, a trick question. The only way to measure the speed of a plane is its movement from one physical point to another. If the conveyor is moving 10mph backwards, then the plane HAS to be moving 10mph forward. If the conveyor is moving to match the speed of the plane, then the plane MUST be in equal opposing motion. The plane can never be stationary and the conveyor be moving, or this quesion is null and void all together.