Need plans or adaptable plan taken from mousetrap powered car.
make a frame and put it conected to a propeller and put a balloon at the top
I (personally) think that if you ripped apart an old sail servo (which is what i'm going to use) at a 1:110 ratio, that the mousetrap could pull a wheel that is connected to the large gear. The small gear would then turn 110 times for every time the large gear went around once. It might not run for very long, but if you use balsa wood of foam, in the right shape, it should (maybe and possibly) fly pretty far. I'll let you know how mine turns out
Search this site for mousetrap or rattrap car.
My first thoughts, though, are that mousetraps are fairly heavy for the amount of energy they store - try gearing your mechanism so that the propeller is turned slowly, and use a large, light body, built for gliding when the power stops.