Fourth Air Force The Fourth Air Force ( 4 AF ) is a numbered air force of the United States Air Force Reserve ( AFRC ) . It is headquartered at March Air Reserve Base , California . 4 AF directs the activities and supervises the training of more than 30 , 000 Air Force Reservists . If called to active duty , 4 AF ' s ready reserve units would be assigned to Air Mobility Command . One of the four original pre – World War II numbered air forces , 4 AF was activated on 18 December 1940 , at March Field , California with a mission of air defense of the Southwestern United States and Lower Midwest regions . During the war , its primary mission became the organization and training of combat units prior to their deployment to the overseas combat air forces . 4 AF is commanded by Maj Gen Mark A . Kyle . Overview . Fourth Air Force is dedicated to ensuring its units and personnel are fully prepared to accomplish all assigned missions in support of national objectives . The sixty person staff consists of Traditional Reservists , Air Reserve Technicians and civilian employees . They direct the activities and supervise the equipping and training of more than 30 , 000 Air Force reservists in unit programs located across the continental United States , Alaska , Hawaii and Guam . Reservists from 4 AF units are routinely deployed to Air Expeditionary units in combat areas of Central and Southwest Asia as part of the Global War on Terrorism . Units . Fourth Air Force flying units include one unit - equipped air mobility and two unit - equipped airlift wings , five unit - equipped air refueling wings , one associate air mobility wing , two associate airlift wings and one associate air refueling group . History . One of the four original numbered air forces , Fourth Air Force was activated as the Southwest Air District of the GHQ Air Force on 18 December 1940 , at March Field , California . It was redesignated Fourth Air Force on 26 March 1941 with a mission for the defense of the Southwest and Lower Midwest regions of the United States . World War II . During World War II Fourth Air Force was the primary air defense command for the West Coast . The command also flew antisubmarine patrols along coastal areas of the Gulf of Mexico from after Pearl Harbor until October 1942 . One of its primary fighter units was the 10th Fighter Wing at Hamilton Field , California . On 29 September 1942 , Rice Municipal Airport located in the Desert Training Center was acquired by the IV Air Support Command , and was operational by 26 October 1942 . Re - designated Rice AAF it was used to train pilots and crews of aircraft whose mission it was to support ground troops . After October 1942 , the antisubmarine patrols were turned over to the Coast Guard and other agencies and the command was engaged primarily in training replacements for combat units . It supported Army Air Forces Training Command ' s mission of training of units , crews , and individuals for bombardment , fighter , and reconnaissance operations . After personnel graduated from AAFTC flight schools ; navigator training ; flexible gunnery schools and various technical schools , Fourth Air Force organized the personnel , aircraft and equipment into combat groups and squadrons . The newly - formed units received secondary training prior to their assignment to the deployed combat air forces in the various overseas theaters . Most P - 51 Mustang and P - 38 Lightning groups were trained by Fourth Air Force primarily due to the proximity of their manufacturing plants in Southern California . By 1944 , most of the Operational Training of groups ended , with the command concentrating on the training of replacement personnel , using Army Air Force Base Units ( AAFBU ) as training organizations at the airfields controlled by Fourth Air Force . Air Defense Wings were also organized for the major metropolitan areas along the West Coast , using training units attached to the Wings . By 1944 the likelihood of an air attack along the West Coast was remote , and these air defense wings were reduced to paper units . On 13 December 1944 , First , Second , Third and Fourth Air Force were all were placed under the unified command of the Continental Air Forces . Air Defense Command . In March 1946 , USAAF Chief General Carl Spaatz had undertaken a major re - organization of the postwar USAAF that had included the establishment of Major Commands ( MAJCOM ) , who would report directly to HQ United States Army Air Forces . Continental Air Forces was inactivated , and Fourth Air Force was assigned to the postwar Air Defense Command in March 1946 and subsequently to Continental Air Command ( ConAC ) in December 1948 being primarily concerned with air defense . The command was headquartered at at Hamilton AFB , California and originally assigned the region of the CONUS west of the Rocky Mountains , roughly from the Pacific Ocean coast east to the eastern borders of , and . It was also responsible for training Air Force Reserve and Air National Guard personnel throughout the region . By 1949 with the establishment of the Western Air Defense Force ( WADF ) , the air defense mission of the command was transferred to WADF , leaving Fourth AF free to focus on its reserve training tasks , which it did for the next decade . On 1 September 1960 , Air Defense Command inactivated Fourth Air Force , transferring its reserve training mission to the Sixth Air Force Reserve Region . Fourth Air Force was re - activated on 20 January 1966 again at Hamilton AFB , as part of Air Defense Command with the inactivation of its organization of Air Defense Sectors . Its area of responsibility was essentially unchanged from its 1948 region . Subordinate organizations assigned by ADC were the 25th 26th and 27th Air Divisions . On 16 January 1968 Air Defense Command was re - designated Aerospace Defense Command ( ADCOM ) as part of a restructuring of USAF air defense forces . Fourth Air Force ' s second period of service was short lived , however , and the command was again inactivated as the result of a major ADCOM reorganization on 31 December 1969 of the First Fourth , Tenth Air Forces and several Air Divisions . This reorganization was the result of the need to eliminate intermediate levels of command in ADCOM driven by budget reductions and a perceived lessening of the need for continental air defense against attacking Soviet aircraft . ADCOM reassigned the units under the inactivated Fourth Air Force were reassigned primarily to the 25th and 26th Air Divisions . Air Force Reserve . The command remained inactive until 8 October 1976 , when it was activated as Fourth Air Force ( Reserve ) at McClellan Air Force Base , CA , and assigned to the Air Force Reserve . Fourth Air Force has been a key component of the Air Force reserve ever since . Fourth Air Force personnel supported operations in Grenada ( Operation Urgent Fury ) and Panama ( Operation Just Cause ) . More than 8 , 000 Air Force Reservists assigned to Fourth Air Force units served in the United States , Europe , and the Persian Gulf during Operation Desert Shield and Desert Storm . This included more than 2 , 878 medical personnel assigned to Fourth Air Force units . Since the end of the Cold War , Fourth Air Force has supported humanitarian missions such as Provide Promise in the Balkans and Provide Relief and Restore Hope in Somalia . Units rushed to provide aid and rescue service to the residents of Florida , the Gulf Coast , and the Caribbean in the aftermath of the traumatic and prolonged 1995 hurricane season . It supported immediate assistance to aid victims and disaster officials following the bombing of the Oklahoma City Federal Building . Fourth Air Force units provided assistance for several natural disasters , including the Northridge ( Los Angeles ) earthquake in 1994 , and the catastrophic midwest floods and the California wildfires in 1993 . Fourth Air Force units routinely support United Nations and Department of State missions . Fourth Air Force people were on the first teams into Haiti for Operation Uphold Democracy , and supported Vigilant Warrior and Desert Thunder deployments to Southwest Asia . The men and women of Fourth Air Force continue to perform international peacekeeping and humanitarian missions on an almost daily basis . Headquarters Fourth Air Force officially returned to its original home , now March Air Reserve Base , in Riverside , CA , in April , 1998 . In 2003 Fourth Air Force became an intermediate echelon responsible primarily for all Air Mobility Command ( AMC ) gained AFRC air refueling units in the United States and AMC gained AFRC strategic airlift units in the western United States .