The Besler Steam Plane
A Travel Air 2000 biplane made the world's first piloted flight under steam power over Oakland, California, on 12 April 1933. The strangest feature of the flight was its relative silence; spectators on the ground could hear the pilot when he called to them from mid-air. The aircraft, piloted by William Besler, had been fitted with a two-cylinder, 150 hp reciprocating engine.
Link courtesy of Ian "Thommo" Thompson