The pilot was attempting to take-off at night from an unlit runway, using the headlights of a car positioned at the upwind threshold for guidance. After becoming airborne the aircraft failed to climb away normally and collided with the car, killing one of the occupants. Although the aircraft had sustained substantial damage it remained airborne, and a safe landing was carried out at the planned destination. It was calculated that the aircraft was travelling at an approximate airspeed of 105 kt when it struck the car. No fault was found with the aircraft that would have prevented it from climbing normally after lift off. The reason the aircraft failed to climb could not be determined.