The De Havilland DH.4 is a British biplane designed by Geoffrey de Havilland and first flown in 1916. It was primarily used during World War I as a light bomber and reconnaissance aircraft. The DH.4 featured a wooden structure with a fabric covering and was powered by a Rolls-Royce Eagle engine, allowing it to reach speeds of around 130 mph. This aircraft was notable for its versatility and effectiveness, serving in various roles throughout the war. The DH.4 was one of the first bombers to carry a payload of bombs and was also used for long-range missions, contributing significantly to the development of military aviation.