This is a typical reference frame error. The plane is not powered by it's wheels, it is powered by either a propellor or a turbine relative to the air. The thrust is placed into the air, not the conveyor. The conveyor can match the planes speed in reverse, that just means that the wheels are turning twice as fast as the plane is moving relative to the air. No matter how fast the conveyor moves, the plane still moves relative to the air. Hence, it will take off. This is a classic mis-direction brain teaser. The one caveat is that if the friction in the wheel bearings/tires create drag equal or greater than the thrust, then the plane cannot accelerate to take off. Of course that would be moot, as the wheels/tires would catch fire, and there would be a big boom fed by aviation fuel.