In VS mode, use the arwing and go up as high as you possibly can. Then, do a U-Turn (Down + C-down). The moment your energy comes back up for you to do another U-Turn, do it immediately. Keep doing U-Turns until your arwing is so far up, it's no longer on the screen. Players might see or lock onto you, but they won't be able to hit you. (Note: If you start coming down after executing the glitch, the terrain gets all messed up)