Ultralight autogyros

The carrier rotor is not driven, it is spun by the forward motion of the vortex. The air flows from below, unlike a helicopter where the air is drawn in from above. Forward motion is provided by the engine, which is predominantly in a pusher configuration. It cannot therefore hang permanently in the air like a helicopter. It's certainly much cheaper than a helicopter. Amateur construction is possible.

There is now a growing interest in autogyros and there are registered pilot training centres.