At first, the obvious answer is: 'No, the plane won't fly.' But it's incorrect, the plane WILL fly. The simplest answer is because the plane's engines work on a different medium (air). Regardless of how fast the conveyor turns, the plane's engines would still be able to pull air into it which makes the air move across its wings which in turn will cause lift and let the plane take off. The only effect the conveyor belt will be is to cause the plane's wheels to spin a helluva lot fast.