Abstract: A propulsion system for a vehicle or toy vehicle is disclosed. The system comprises rotary drive means for driving the vehicle along ground, the rotary drive means operating in a plane and having a peripheral ground-engagement part. The system further comprises a rotor comprising one or more rotor blades rotatable about a rotor axis for producing thrust, wherein the rotary drive means and the rotor are positioned relative to each other so that during rotation of the rotor, the rotor blades pass through the plane of the rotary drive means, inside the peripheral ground-engagement part. In this way, the rotor blades are protected by the peripheral ground-engagement part.