My conclusion, after some thought, is that it would take off, because an airplane is propelled by engine thrust, and the wheels play no part in its movement. My only confusion is if it is actually possible for the conveyer belt to actually spin the same speed as the wheels. I think once the plane starts moving forward (when the engines power up), the conveyer will have to spin faster to account for the movement, which - if it happens simultaneously - is an impossibility. (Because it has to spin same as wheel spin + airplane movement. And as the conveyer spins, the wheel spin increases at the same time. So it is essentially impossible for it to spin at wheel spin speed + airplane movement.)