USAAF’s Declaration of Independence

Dec. 1, 2006

“War Department Field Manual FM 100-20:

Command and Employment of Airpower”

United States War Department

Washington, D.C.

July 21, 1943


In World War II, the drive for a separate US air arm moved two giant steps forward. In March 1942, the Army’s “Circular 59, War Department Reorganization,” declared the Army Air Forces to be autonomous. Then, on July 21, 1943, the cause got an even bigger boost—publication of “War Department Field Manual (FM) 100-20, Command and Employment of Airpower.”

The document, approved by Gen. George C. Marshall, the Army Chief of Staff, reflected lessons of unsuccessful operations in North Africa in 1942, when ground commanders parceled out air forces piecemeal to ground units. FM 100-20 signaled a new day; it said air and ground forces were equal, that air superiority was “the requirement” for success on land, and that an air commander should have centralized control over airpower in a theater. Some historians now consider it the air arm’s “declaration of independence.”

Relationship of Forces—Land power and airpower are co-equal and interdependent forces; neither is an auxiliary of the other.

Doctrine of Employment—Air superiority is the requirement for the success of any major land operation. Air forces may be properly and profitably employed against enemy sea power, land power, and airpower; however, land forces operating without air superiority must take such extensive security measures against hostile air attack that their mobility and ability to defeat the enemy land forces are greatly reduced. Therefore, air forces must be employed primarily against the enemy’s air forces until air superiority is obtained. In this way only can destructive and demoralizing air attacks against land forces be minimized and the inherent mobility of modern land and air forces be exploited to the fullest.

Command of Airpower—The inherent flexibility of airpower is its greatest asset. This flexibility makes it possible to employ the whole weight of the available airpower against selected areas in turn; such concentrated use of the air striking force is a battle winning factor of the first importance. Control of available airpower must be centralized and command must be exercised through the air force commander if this inherent flexibility and ability to deliver a decisive blow are to be fully exploited. Therefore, the command of air and ground forces in a theater of operations will be vested in the superior commander charged with the actual conduct of operations in the theater, who will exercise command of air forces through the air force commander and command of ground forces through the ground force commander. The superior commander will not attach Army air forces to units of the ground forces under his command except when such ground force units are operating independently or are isolated by distance or lack of communication. …

In a theater of operations, there will normally be one air force. This air force will be organized in accordance with the task it is required to perform in any particular theater and, therefore, no set organization of an air force can be prescribed. …

The combat operations in which air force units are engaged are directed toward the accomplishment of the following basic tasks: (a) Destroy hostile air forces. This will be accomplished by attacks against aircraft in the air and on the ground and against those enemy installations that he requires for the application of airpower. (b) Deny the establishment and destroy existing hostile bases from which an enemy can conduct operations on land, sea, or in the air. (c) Operate against hostile land or sea forces, the location and strength of which are such as to threaten the vital interests of the United States or its Allies. (d) Wage offensive air warfare against the sources of strength, military and economic, of the enemies of the United States and its Allies, in the furtherance of approved war policies. (e) Operate as a part of the task forces in the conduct of military operations. (f) Operate in conjunction with or in lieu of naval forces. …

In order to obtain flexibility, the operations of the constituent units of a large air force must be closely coordinated. Flexibility enables airpower to be switched quickly from one objective to another in the theater of operations. Control of available airpower in the theater must be centralized and command must be exercised through the air force commander. …

Generally, the aim of the strategic air force is the defeat of the enemy nation. Missions are selected which make a maximum contribution to this aim. Objectives may be found in the vital centers in the enemy’s lines of communication and important establishments in the economic system of the hostile country. …

The mission of the tactical air force consists of three phases of operations in the following order of priority: (1) First priority—To gain the necessary degree of air superiority. This will be accomplished by attacks against aircraft in the air and on the ground, and against those enemy installations that he requires for the application of airpower. (2) Second priority—To prevent the movement of hostile troops and supplies into the theater of operations or within the theater. (3) Third priority—To participate in the combined effort of the air and ground forces, in the battle area, to gain objectives on the immediate front of the ground forces.