Description:00 08 33 00 History of the aviation. The 30s. Pioneers, inventions, prototypes, transport, communications, armament. Development of bombers, LB 7 , B4. Demonstration in California, March Field. Seen on squadron of plane bomber in the sky. Seen on Douglas DC3, first plane big line in 1936, will be used during 20 years. Seen on the DC3 in sky, plane for tourism. On 1938, appearance of Douglas DC4. Close-up of this plane on the ground. Cargo plane. Takeoff of this plane.