503d Air Defense Group The 503d Air Defense Group is an inactive United States Air Force organization . Its last assignment was with the 25th Air Division of Air Defense Command at Portland International Airport , Oregon . It was inactivated on 18 August 1955 . The group was originally activated as a support group at the end of World War II and provided logistics and administrative support for the 86th Fighter Group in Germany until 1946 , when the group returned to the United States , where it supported the 56th Fighter Group . It was discontinued when the USAF reorganized its combat and support units on its bases into a single wing . The group was activated once again in 1953 , when ADC established it as the headquarters for two dispersed fighter - interceptor squadrons and the medical , maintenance , and administrative squadrons supporting them . It was replaced in 1955 when ADC transferred its mission , equipment , and personnel to the 337th Fighter Group in a project that replaced air defense groups commanding fighter squadrons with fighter groups with distinguished records during World War II . History . World War II . The group was activated as the 503d Air Service Group toward the end of World War II , shortly after V - E Day in a reorganization of Army Air Forces ( AAF ) support groups in which the AAF replaced Service Groups that included personnel from other branches of the Army and supported two combat groups with Air Service Groups including only Air Corps units . Designed to support a single combat group . Its 921st Air Engineering Squadron provided maintenance that was beyond the capability of the combat group , its 745th Air Materiel Squadron handled all supply matters , and its Headquarters & Base Services Squadron provided other support . it supported the 86th Fighter Group , as part of the occupation forces in Germany until 1946 . The group returned to the US and supported the 56th Fighter Group at Selfridge Field , Michigan In October 1946 , the group deployed a detachment to Ladd Field , Alaska for Arctic Training . In 1947 the group and its squadrons were inactivated and replaced the 56th Airdrome Group , 56th Maintenance & Supply Group , and 56th Station Medical Group as the Air Force began a service test of the Wing / Base reorganization ( Hobson Plan ) , which was adopted to unify control at air bases . It was disbanded in 1948 . Cold War . During the Cold War The group was reconstituted , redesignated as the 503d Air Defense Group , and activated at Portland International Airport 18 February 1953 , with the mission to train and maintain interceptor squadrons in state of readiness in order to defend Northwest United States . The 357th Fighter - Interceptor Squadron ( FIS ) , which was already stationed at Portland International Airport and Flying North American F - 86 Sabre s was assigned as the operational component of the group . The group replaced the 89th Air Base Squadron as host organization for active duty USAF units at Portland International Airport . It was assigned three squadrons to perform its support responsibilities . Two days later , the 497th Fighter - Interceptor Squadron , flying Lockheed F - 94 Starfire aircraft equipped with airborne intercept radar and armed with 20 mm cannons , was activated as the group ' s permanent operational squadron . In May 1953 , the 357th FIS was transferred to French Morocco and was reassigned . In 1954 , the 497th FIS converted to Northrop F - 89 Scorpion aircraft armed with HVAR rocket s . The group was inactivated and replaced by the 337th Fighter Group ( Defense ) in 1955 as part of ADC ' s Project Arrow , which was designed to bring back on the active list the fighter units which had compiled memorable records in the two world wars . The group was disbanded once again in 1984 , but reconstituted in 1985 as a base support organization . It has never been active since then . References . Bibliography . Further reading