The
Airco DH.4 was a
British two-seat
biplane day bomber of
World War I. It was designed by
Geoffrey de Havilland (hence "DH") for
Airco, and was the first British two-seat light day-bomber to have an effective defensive armament. It first flew in August 1916 and entered service with the
Royal Flying Corps (RFC) in March 1917. The majority of DH.4s were actually built as general purpose two-seaters in the
United States, for service with the American forces in France.