At a R&D cost of $600,000, Lockheed produced the YP-38 prototype aircraft in 1938. They ran a cross country test from California to Mitchel Field in Long Island, New York (which is now host to the Air and Space Museum, as well as numerous other museums).
The plane had problems though, specifically the carburetor which caused the plane to crash; however, the pilot survived. Despite the accident, the army was impressed enough that they ordered 13 YP-38s.
The original design of the Lockheed P-38 Lightning was to be a bomber and not a fighter, but when confronted by the Japanese Zero airplane, the pride of the Japanese air force, the P-38 was faster and more formidable than the Zero, knocking out more Japanese airplanes than any other fighter in World War II, and was the only truly successful twin-engine fighter.
The plane saw most of its fighting in the Pacific Theater and was the primary fighter until the P-51D Mustangs came in toward the end of the war.
Initially, the total order of the plane was for 50, but the military started to request more of this aircraft, so production was accelerated and the P-38 would become the plane that represented the fastest fighter production than any other plane in the world.
Specs are the following:
Top speed: 443 mph
Manufacturer: Lockheed Corporation