A car capable of 80 mph, assuming some gearbox/rpm headroom, will jump off the 80mph treadmill too, normally there's a lot of drag to overcome which isn't there

A car capable of 80 mph, assuming some gearbox/rpm headroom, will jump off the 80mph treadmill too, normally there's a lot of drag to overcome which isn't there on a treadmill. The second paragraph checks out: with a realistic plane on an unrealistic treadmill either the wheels will fall off or the treadmill will produce enough airspeed to lift off the plane vertically up.