566th Air Defense Group The 566th Air Defense Group is a disbanded unit of the United States Air Force . Its last assignment was with the 28th Air Division at Hamilton Air Force Base ( AFB ) , California where it was inactivated on 18 August 1955 . The group was originally activated as a support unit for a combat group at the end of World War II but never deployed before it was inactivated in 1945 . The group was activated once again in 1952 to replace the support elements of the inactivating 78th Fighter - Interceptor Wing . A year later ADC established it as an operational headquarters for fighter - interceptor squadrons as well . It was replaced in 1955 when ADC transferred its mission , equipment , and personnel to the 78th Fighter Group in a project that replaced air defense groups commanding fighter squadron s with fighter groups with distinguished records during World War II . History . World War II . The group was activated toward the end of World War II as the 566th Air Service Group in 1944 and trained to support a single combat group . Its 984th Air Engineering Squadron would provide maintenance that was beyond the capability of the combat group , its 1004th Air Materiel Squadron would handle all supply matters , and its Headquarters & Base Services Squadron would provide other support . The group was inactivated before it could be deployed overseas . It was disbanded in 1948 . Cold War . During the Cold War the group was reconstituted , redesignated as the 566th Air Base Group , and activated at Hamilton AFB in 1952 in a major reorganization of Air Defense Command ( ADC ) responding to ADC ' s difficulty under the existing wing base organizational structure in deploying fighter squadrons to best advantage . It replaced the 78th Air Base Group as host unit for Hamilton . It was assigned eight squadron s and one flight to perform its support responsibilities . The group also assumed responsibility to maintain aircraft stationed at Hamilton from the inactivating 78th Maintenance & Supply Group , while the operational elements of the 78th Fighter - Interceptor Wing were assigned to the 28th Air Division . The 566th was redesignated the 566th Air Defense Group and assumed responsibility for air defense of the Northern California . It was assigned the 84th Fighter - Interceptor Squadron ( FIS ) , flying F - 89 Scorpion aircraft from the 28th Air Division as its operational element . The 84th FIS was already stationed at Hamilton AFB . In March , a second operational squadron , the 496th Fighter - Interceptor Squadron , was activated at Hamilton and assigned to the group . The 496th FIS was initially equipped with outmoded World War II era F - 51 Mustang Aircraft . In April , the 83rd FIS traded its Scorpions for F - 94 " Starfire " aircraft . and to later model Starfire before the end of the year . The 496th FIS , in turn converted to F - 86 " Sabres " during 1953 . In February 1954 , the 325th Fighter - Interceptor Squadron at Travis Air Force Base , CA , flying F - 86 Sabres , was assigned to the group . Ten days after its assignment , the 325th FIS moved to Hamilton AFB . A few months later , in July , the group once again had only two operational squadrons when the 496th FIS transferred to Europe and was assigned elsewhere . The 566th was inactivated and replaced by the 78th Fighter Group ( Air Defense ) on 18 August 1955 as result 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 . References . Bibliography . Further Reading