Fourth Air Force

Fourth Air Force is a Numbered Air Force of the United States Air Force with a storied history in air defense and training. Headquartered at March Air Reserve Base in California, it is a vital component of Air Combat Command and is assigned to First Air Force (Air Forces Northern), focusing on the defense of the continental United States. Its mission encompasses homeland security, domestic disaster response, and providing combat-ready forces for global deployment.

History

The unit was initially activated as the **Fourth Air Force** on 18 December 1940 at March Field, California, under the United States Army Air Corps. During World War II, it served as a primary training and air defense command for the West Coast of the United States, responding to fears of attack following the attack on Pearl Harbor. It was responsible for the air defense of critical areas including Los Angeles, San Francisco, and the Pacific Northwest, and its units engaged in patrols and intercept missions. Post-war, it transitioned through various roles under Continental Air Command and Tactical Air Command, and was briefly inactivated in the 1960s before being reactivated in 1976 as part of the reorganization of Air Defense Command.

Organization

The command is organized under the dual-hatted structure of First Air Force (Air Forces Northern), which reports to both Air Combat Command and the North American Aerospace Defense Command (NORAD). It does not command flying units directly but oversees the operational readiness and tasking of assigned Air National Guard and Air Force Reserve units across the western United States. Its area of responsibility includes the states of California, Nevada, Arizona, Utah, Colorado, and New Mexico, coordinating with other agencies like the Federal Emergency Management Agency and United States Northern Command.

Current operations

Today, its primary mission is **homeland defense** and **air sovereignty** for the western United States, operating under the **Continental United States North American Aerospace Defense Command Region** (CONR). It maintains a constant alert posture, with fighter aircraft ready to identify and intercept unknown aircraft approaching U.S. airspace. The force also plays a key role in **Operation Noble Eagle**, the ongoing domestic air patrol mission initiated after the September 11 attacks. Furthermore, it provides support for civil authorities during natural disasters, such as wildfires in California or hurricanes, and supports counter-drug operations along the Southwest border.

Previous designations

Throughout its history, the organization has been known by several official designations reflecting its changing mission. It was originally constituted and activated as the **4th Air Force** in 1940. In September 1942, it was redesignated as **Fourth Air Force**. After being inactivated in 1960, it was reactivated in 1976 as **Fourth Air Force (Reserve)** under the new Air Force Reserve command structure. In 1994, it was integrated into the Air Combat Command and First Air Force framework, dropping the "(Reserve)" designation and returning to its traditional role in continental air defense.

Aircraft

While it does not own aircraft, it exercises operational control over various fighter, airlift, and tanker aircraft flown by its assigned Air National Guard and Air Force Reserve units. Typical fighter aircraft include the F-15 Eagle, F-16 Fighting Falcon, and the newer F-22 Raptor and F-35 Lightning II. Airlift support often involves the C-130 Hercules and C-17 Globemaster III, while aerial refueling is provided by KC-135 Stratotanker and KC-46 Pegasus aircraft. These assets are integral to performing its air defense, disaster response, and global mobility missions.

Bases

Its headquarters is located at March Air Reserve Base, a major installation originally known as March Field. Key operational locations for its assigned units include Joint Base San Antonio (support functions), Naval Air Station Joint Reserve Base Fort Worth, Davis-Monthan Air Force Base in Arizona, and Buckley Space Force Base in Colorado. Other significant installations hosting associated flying units are Nellis Air Force Base, Luke Air Force Base, and Portland Air National Guard Base, which serve as hubs for training, operations, and alert facilities.