Fourth Air Force
Fourth Air Force - Emblem.png
Shield of the Fourth Air Force
Active1 December 1985 - present (as Fourth Air Force)
24 September 1976 - 1 December 1985 (as Fourth Air Force (Reserve))
20 January 1966 - 30 September 1969
18 September 1942 - 1 September 1960 (as Fourth Air Force)
26 March 1941 - 18 September 1942 (as 4 Air Force)
19 October 1940 - 26 March 1941 (as Southwest Air District)
(82 years, 2 months)[1]
Country United States of America
Branch United States Air Force (18 September 1947 – present)
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United States Army (
US Army Air Corps Hap Arnold Wings.svg
Army Air Forces, 20 June 1941 – 18 September 1947;
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Army Air Corps 19 October 1940 – 20 June 1941)
TypeNumbered Air Force
RoleProvide combat-ready reserve air mobility and support forces[2]
Part of
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Air Force Reserve Command
HeadquartersMarch Air Reserve Base, California, U.S.
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World War II – American Theater[3]
US Air Force Outstanding Unit Award - Stremer.jpg

Air Force Outstanding Unit Award
CommanderBrig Gen Derin S. Durham
Vice CommanderCol Michael M. Moeding
Command ChiefCCM Israel Nuñez
Carroll W. McColpin
Benjamin H. King

The Fourth Air Force (4 AF) is a numbered air force of the Air Force Reserve Command (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, Air Education and Training Command, and Pacific Air Forces.[4] Several airfields are associated with the Fourth Air Force.

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 Brigadier General Derin S. Durham.


Fourth Air Force flying units include one unit-equipped air mobility and two unit-equipped airlift wings, five unit-equipped air refueling wings, three associate air mobility wings, two associate airlift wings and one associate air refueling wing.


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

Fourth Air Force region of the United States, early World War II
Fourth Air Force region of the United States, early 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.

Beginning in May 1942, the mission of Fourth Air Force became operational training of units and crews, and the replacement training of individuals for bombardment, fighter, and reconnaissance operations. It received graduates of Army Air Forces Training Command flight schools; navigator training; flexible gunnery schools and various technical schools, organized them into newly activated combat groups and squadrons, and provided operational unit training (OTU) and replacement training (RTU) to prepare groups and replacements for deployment overseas to combat theaters. The Fourth Air Force became predominantly a fighter OTU and RTU organization. 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 RTU training of individual replacements 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 a full-scale air attack along the West Coast since the bombing of Dutch Harbor two years earlier 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 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 newest Boeing C-17A Globemaster III, 06-6164, arrives at Travis AFB
The newest Boeing C-17A Globemaster III, 06-6164, arrives at Travis AFB
A KC-135R Stratotanker from the 434th Air Refueling Wing refuels an F-22A from the 1st Fighter Wing, Langley Air Force Base, Virginia
A KC-135R Stratotanker from the 434th Air Refueling Wing refuels an F-22A from the 1st Fighter Wing, Langley Air Force Base, Virginia

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 1994 Northridge earthquake in the Los Angeles area, 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 gained AFRC air refueling units in the United States and AMC gained AFRC strategic airlift units in the western United States. Today 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 were routinely deployed with Air Expeditionary units to fight in the Afghanistan War (2001-2021); the Iraq War (2003-2011); and later anti-ISIS (Daesh) operations.


Activated on 18 December 1940
Redesignated: 4 Air Force on 26 March 1941
Redesignated; Fourth Air Force on 18 September 1942
Discontinued, and inactivated on 1 September 1960
Organized on 1 April 1966
Inactivated on 30 September 1969
Activated in the Reserve on 8 October 1976
Redesignated Fourth Air Force on 1 December 1985.







Air Divisions



Groups (incomplete)

List of commanders

No. Commander Term
Portrait Name Took office Left office Term length
John C. Flournoy Jr.
Major General
John C. Flournoy Jr.
3 November 20137 February 20173 years, 96 days
Randall A. Ogden
Major General
Randall A. Ogden
7 February 20177 April 20203 years, 60 days
Jeffrey T. Pennington
Major General
Jeffrey T. Pennington
~7 April 2020August 2022~2 years, 116 days
Derin S. Durham
Brigadier General
Derin S. Durham
10 September 2022Incumbent129 days


Public Domain This article incorporates public domain material from the Air Force Historical Research Agency.

  • Maurer, Maurer (1983). Air Force Combat Units of World War II. Maxwell AFB, Alabama: Office of Air Force History. ISBN 0-89201-092-4.
  • Ravenstein, Charles A. (1984). Air Force Combat Wings Lineage and Honors Histories 1947–1977. Maxwell AFB, Alabama: Office of Air Force History. ISBN 0-912799-12-9.
  • A Handbook of Aerospace Defense Organization 1946–1980, by Lloyd H. Cornett and Mildred W. Johnson, Office of History, Aerospace Defense Center, Peterson Air Force Base, Colorado
  • Winkler, David F. (1997), Searching the skies: the legacy of the United States Cold War defense radar program. Prepared for United States Air Force Headquarters Air Combat Command.
The Museum is located off the grounds of the Base and displays in its aircraft collection examples bombers, fighters, cargo, refueling and reconnaissance aircraft, many of which served at March Field, March AFB and/or March ARB.