July 4, 1942. The first Army Air Force bomber mission over western Europe in World War II is flown by B 17s of the 97th Bombardment Group against the Rouen-Sotteville Railyards in France. Flying Fortress is one of the most famous airplanes ever built. The B-17 prototype first flew on July 28, 1935. Few B-17s were in service on December 7, 1941, but production quickly accelerated. The aircraft served in every WW II combat zone, but is best known for daylight strategic bombing of German industrial targets.