I know Delta was marketing their Austin or San Antonio to Detroit flight as a flight of totality. Yes, aircraft fly over the clouds and therefore can experience the eclipse even if there are clouds below. And because they are flying in the same direction as the moon shadow, their time of totality will be longer than on the ground, assuming they are flying exactly on the path of totality.
I doubt that anybody will see the corona from the aircraft since the sun will be pretty exactly in the rear, maybe slightly on the right side. Unless, of course they are installing a glass ceiling or use one of those fancy Boeings 737 Max where the door plugs are being jettisoned during the flight.