505th Bombardment Group The 505th Bombardment Group is an inactive United States Air Force unit . Its last assignment was with Thirteenth Air Force , stationed at Clark Field , Philippines . It was inactivated on 30 June 1946 . The unit served primarily in the Pacific Ocean theater of World War II as part of Twentieth Air Force . The 505th Bomb Group ' s aircraft engaged in B - 29 Superfortress bombardment operations against Japan . Its aircraft were identified by a " K " ( January to March 1945 ) or " W " ( April to September 1945 ) inside a Circle painted on the tail . History . The unit was established in early 1944 at Dalhart Army Air Field , Texas , being formed as a B - 29 Superfortress Very Heavy bombardment Group . Thu unit was formed with four bomb squadrons , being a mixture of both new and reassigned units . The 482d , 484th and 485th having World War I origins and the 483d being a newly - constituted unit . Due to a shortage of B - 29s , the group was equipped with former II Bomber Command B - 17 Flying Fortress es previously used for training heavy bomber replacement personnel . The group was eventually equipped with newly - manufactured B - 29 Superfortresses at Harvard Army Airfield , Nebraska during the summer of 1944 . In May shortages in aircraft and equipment led to the 485th Bomb Squadron being inactivated , with its personnel being consolidated into other group squadrons and the 505th becoming a three squadron group ( the 485th would be reactivated a month later as part of the 501st Bombardment Group ) . The 505th was deployed to Pacific Theater of Operations ( PTO ) in late 1944 , being assigned to the XXI Bomber Command 313th Bombardment Wing in the Northern Mariana Islands ; being stationed at North Field , Tinian . It entered combat in February 1945 with strikes on Iwo Jima and the Truk Islands . It then began flying very long range strategic bombardment missions over the Japanese Home Islands , attacking military , industrial and transportation targets . Switched to night incendiary raids attacking major Japanese cities in the spring of 1945 , causing massive destruction of urbanized areas . The 505th Bomb Group received a Distinguished Unit Citation for a strike against the Nakajima aircraft factory at Ota in February 1945 . Conducted incendiary raids on area targets in Japan , carrying out these missions at night and at low altitude . Bombed in support of the Allied assault on Okinawa in April 1945 . Engaged in mining operations against Japanese shipping , receiving second DUC for mining the Shimonoseki Strait and harbors of the Inland sea , June – July 1945 . The group continued strategic bombing raids and incendiary attacks until the Japanese Capitulation in August 1945 . After V - J Day , the 505th dropped supplies to Allied prisoners , participated in show - of - force missions , and flew over Japan to evaluate bombardment damage . In the fall of 1945 , the group largely demobilized as part of the " Sunset Project " , with some aircraft being sent reclamation on Tinian ; others being returned to the United States for storage at aircraft depots in the southwest . By Christmas , the group fleet was reduced to 30 or less planes Many of the remaining veterans signed for " any conditions of travel " to get home , arriving three weeks later in Oakland , California , where troop trains scattered them for points of discharge close to their homes . The unit was largely a paper organization when it was reassigned to Clark Field in the Philippines in March 1946 , and assigned to Thirteenth Air Force . At Clark its remaining aircraft and personnel were consolidated into other units , and it was inactivated in June .