21st Bombardment Squadron The 21st Bombardment Squadron is an inactive United States Air Force unit . Its last assignment was with the 501st Bombardment Group , based at Northwest Field , Guam in the Mariana Islands . It was inactivated on 10 June 1946 . The 21st Bombardment Squadron was one of the first squadrons to make a land - based attack on the Japanese home islands on 18 July 1943 , flying B - 24 Liberator s . This raid , against Shimushu and Paramushiru in the Kuril Islands , caused little or no damage , but was only the first of a long series of attacks on Japan from the north . Inactivated in 1943 ; the 21st later was reorganized as a B - 29 Superfortress Bomb Squadron and engaged in combat over Japan in 1945 . History . Established as a Fourth Air Force bombardment squadron in November 1940 as part of the USAAC ' s buildup of forces after the outbreak of World War II in Europe ; equipped with B - 18 Bolo s and early YB - 17 Flying Fortress prototypes . Deployed to Third Air Force after the Attack on Pearl Harbor , engaged in antisubmarine patrols with Lockheed A - 29 Hudson s over the southeast Atlantic coastline . Flew its first anti - submarine warfare patrols over the waters off Savannah , Georgia . Returned to California and flew regular patrols with the Hudson began on 9 January 1942 , from Muroc Army Airfield , and the squadron continued to fly ASW patrols until June 1942 , at one point operating from five bases on the west coast at the same time . Deployed to Alaska as part of Eleventh Air Force , became part of forces engaged in combat against Japanese forces in the Aleutian Campaign , 11 June 1942 – 14 August 1943 flying B - 24 Liberator s . The squadron would remain officially part of the 30th Bombardment Group , however it operated under the command of the 28th Composite Group in the Aleutians . The first aircraft began operating from Fort Glenn Army Airfield , Umnak Island , at the eastern end of the Aleutian chain , on 11 June 1942 , and the entire squadron was in place by 3 September . During this period Adak Army Airfield had been under construction on Adak Island , and on 14 September six B - 24s from the 21st Bombardment Squadron took part in the first major raid to be launched from this airbase . This saw twelve B - 24s from the 21st and 404th Bombardment Squadrons attack the Japanese base on Kiska , sinking two mine sweepers and damaging the camp and submarine area . This attack would be followed by a long series of attacks on the Japanese positions on Kiska and Amchitka . By February 1943 Amchitka Island was back in American hands , and the 21st moved to that island on 18 February 1943 , operating from Amchitka Army Airfield until July . On 18 July 1943 the 21st , 36th and 404th Bombardment Squadrons each contributed some of the six B - 24s that became the first Liberators ( and the first Air Force bombers since the Doolittle Raid ) to attack the Japanese home islands . On 26 August 1943 , after the liberation of Kiska Island , the 21st Bombardment Squadron became one of a number of units of the Eleventh Air Force that were ordered to prepare for a move back to the Continental United States . That move finally began on 19 September 1943 , and the squadron was inactivated on 1 November 1943 . A new 21st Bombardment Squadron ( unrelated to previous ) was constituted and activated under Second Air Force as Very Heavy ( B - 29 Superfortress ) squadron , April 1944 . Not manned or equipped . Reactivated in June 1944 at Dalhart Army Airfield , Texas as part of the 501st Bombardment Group . Trained in B - 29 operations , although training was delayed for an extended time due to shortages of B - 29 aircraft . Equipped with B - 29B aircraft , built for fast , low - level attacks . It had all but the tail defensive armament removed , since experience had shown that by 1944 the only significant Japanese fighter attacks were coming from the rear . Deployed to Northwest Field , Guam . As the crews arrived they commenced ground school and shakedown missions over Rota , Pajoros and Truk . Entered combat on 19 June 1945 when its B - 29 ’ s bombed Japanese fortifications in the Truk Islands . Flew its first mission against Japan on 27 June 1945 , and afterward operated principally against the enemy ’ s petroleum industry on Honshu . Flew 15 combat missions before the war ended , then flew numerous missions airdropping food and supplies for Allied prisoners in POW camps across Japan , Korea , Manchuria and China . In September 1945 , several flights were made to Chitose Airfield in Hokkaido near Sapporo with gasoline for the first nonstop flight from Japan to the United States by Generals Giles and LeMay . Personnel returned to United States during early 1946 . Inactivated on Guam June 1946 , aircraft flown to storage in western United States .