Northrop Aircraft Co. pioneered the flying-wing design and developed the YB-49, which first flew in 1947.
The YB-49 was the culmination of years of development, which began with the Northrop Model 1 (N-1M), a twin-engine flying model, in 1939. Northrop began improving on the N-1M and developed the XB-35 and YB-35,
both of which were propeller-powered flying wings. In 1946, the XB-35
took its first test flight. Jet propulsion was then added to the YB-35
model, creating the YB-49. A year later, the YB-49 took its maiden
flight in California.