Not a helicopter - an autogyro. The rotor on the top is not driven (literally just spins freely on a bearing). Forward motion pushes air through it, which keeps it spinning and that keeps the aircraft up. In effect the rotor acts like a wing (forward motion results in lift), but without the ability to stall.

I'm learning to fly an autogyro in the UK. They're great fun to fly, and in theory safer than a plane because the short landing distance means that in event of engine failure you have a much greater selection of places to land (in practice modern safe autogyros have only been around 5-10 years so we don't have enough data to compare).