High Quality Content by WIKIPEDIA articles! No. 604 Squadron RAF was a squadron of the Royal Air Force noted for its pioneering role the development of radar-controlled night-fighter operations. The squadron was established in March 1930 at RAF Hendon as a day-bomber squadron of the Royal Auxiliary Air Force. In July 1934, the squadron transitioned to two-seat fighters. Shortly after the commencement of World War II in 1939, the squadron was reassigned to a night-fighter role.