I know that some owners of ultralights are former pilots who've failed their medicals but still want to fly. I can't say I blame them; what an exhilarating feeling leaving the ground. Keep the nitro readily accessible though.
That being said, I've heard that a powered parachute will just slowly descend to the ground if there's a loss of power. Nice feature. I've seen them down at the bay and I'd LOVE to take one of them for a whirl!
If you hear someone soaring over your head this Summer screaming like a nine-year-old girl, that'd probably be me.