Go to the cannon left of the summit or the Chomp Chomp that is near the more open area. Aim the cannon all the way to the sun, then point it at the cloud below the sun. Set it so that the bottom arrow of the target is almost touching the middle bottom part of the cloud. Then, fire. You should fly into a fence and the top part of the screen will turn blue. You will fall straight out of the sky. You can even go out of the level if you try to move with the D-pad while still high in the sky.