Sikorsky HNS-1 hoverfly helicopter undergoing test flights. This helicopter, designed by Igor Sikorsky, was the world's first mass-produced helicopter. It was also the first helicopter to land aboard a ship and performed the first rescue by helicopter. It was used by the US Navy, US Army, US Coastguard, Royal Navy and the RAF. Photographed at Langley Air Force Base, Virginia, USA, in March 1945.