I'm swimming against a current that is equal my swim speed.(conveyor) Im going nowhere. But if I grab a branch of a tree(prop aganst air) and pull forward I can make headway. But if the current increased just as I pulled forward. It would come down to strength over friction. If the current speed was increased enough to over power me(friction of wheel bearings) I would never "fly".

Now we can interpret how the riddle is worded to make both scenarios possible.

Obviously an airplane can overcome its wheelbearing friction. And the riddle said the conveyor would just match the planes speed. It did not say it would run a milliion RPMs and sieze the wheel bearings . If the plane is achieving "airspeed" Meaning just that, air speed over the wing,. Then I know it will fly.