If you put a plane on a treadmill and start the treadmill it will initially move backwards. If you start the engines, it will move forward, there is basically no way to keep the plane motionless in respect to the ground. That being said, we think of speed like our speedometer in our cars, but a planes measures it by airspeed, therefore to say that the treadmill is matching the speed of the plane, it must be moving releative to the ground, not the belt of the treadmill and therefore would have drag and lift etc...
