In June 1936, the Hurricane went into production for the Air Ministry; it entered squadron service on 25 December 1937. Its manufacture and maintenance was eased by using conventional construction methods so that squadrons could perform many major repairs without external support. The Hurricane was rapidly procured prior to the outbreak of the Second World War in September 1939, when the RAF had 18 Hurricane-equipped squadrons in service. The aircraft was relied on to defend against German aircraft operated by the Luftwaffe, including dogfighting with Messerschmitt Bf 109s in multiple theatres of action.