Ultralights can actually take off on their own. You might be thinking of classic Elmira-type gliders. The ultralights are pretty much a tricycle gear, hang glider wings and a lawn mower engine with a deck chair strapped in if the operator wants a little comfort.
I exaggerate, but not too much.
Thanks for correcting me. This could be serious then!!! These ultralights can only carry a pilot, right? How much weight can they carry?