Berliner Helicopter
 The Berliner Helicopters were a series of experimental helicopters built by Henry Berliner between 1922 and 1925. The helicopters had only limited controllability but were the most significant step forward in helicopter design in the USA until the production of the Vought-Sikorsky VS-300 helicopter in 1940. The 1922 flights of the Berliner and the de Bothezat H1 were the first by manned helicopters.