Technically the snail can't actually fly. But neither can flying fish, and if they deserve to have flight in their name then so does this app.
Snail Can Fly is a momentum based jumping game. Touching the screen pulls your character down to earth, and releasing (with proper timing) flings it back into the air. By timing your descent to align with a downslope, you'll ramp off of the hills while building speed and height.
The game offers a number of character options, ranging from the snail (of icon fame), to a crocodile, to a questionably licensed Superman. Although playing without the snail is like playing Super Mario Brothers without Mario. Peach? Luigi? Come on.