The MX-334 emerged as a flying wing glider with no tail surfaces, similar in layout and construction to the Northrop N-9M. Completed in late Spring 1943 the no.1 MX-334 was tested in NACA Langley's wind tunnel, after which a large wire-braced fin was added to ensure directional stability at high speeds. The first flight attempts was carried out by the no.2 aircraft towed behind a Cadillac car for low level take-off and landing tests, with no success. After modifications the first launch was carried out on 4 September 1943, towed behind a large truck. For more comprehensive testing, a Lockheed P-38 Lightning was used to tow the aircraft on its first proper flight on 2 October 1943.