i Used a Pylon racer P-51 and went straight up till it ran out of gas. i think i hit about 12,000 climbing at 200mph!! the glide down took a long time.

It flips over because you are flying right over the "camra". its just like if you were standing on the ground and flew right over your head, you would have to turn around really quick as it started going over the other way. So if it keeps flipping over then you know you are going straight up.