High Quality Content by WIKIPEDIA articles! The Northrop P-61 Black Widow was the first operational U.S. military aircraft designed specifically for night interception of aircraft, and was the first aircraft specifically designed to use radar. It was an all-metal, twin-engine, twin-boom design developed during World War II. The first test flight was made on 26 May 1942, with the first production aircraft rolling off the assembly line in October 1943. The last aircraft was retired from government service in 1954.