Air Corps Tactical School

The Air Corps Tactical School, also known as ACTS and "the Tactical School", was a military professional development school for officers of the United States Army Air Service and United States Army Air Corps, the first such school in the world. Created in 1920 at Langley Field, Virginia, it relocated to Maxwell Field, Alabama, in July 1931. Instruction at the school was suspended in 1940, anticipating the entry of the United States into World War II, and the school was dissolved shortly after. ACTS was replaced in November 1942 by the Army Air Force School of Applied Tactics.

In addition to the training of officers in more than 20 areas of military education, the school became the doctrine development center of the Air Corps, and a preparatory school for Air Corps officers aspiring to attendance at the U.S. Army's Command and General Staff College. The motto of the Air Corps Tactical School was Proficimus More Irretenti—"We Make Progress Unhindered by Custom."

The Air Corps Tactical School was notable as the birthplace of the Army Air Forces doctrine of daylight precision bombing. This doctrine held that a campaign of daylight air attacks against critical targets of a potential enemy's industrial infrastructure, using long range bombers heavily armed for self-defense, could defeat an enemy nation even though its army and navy remained intact. The Tactical School, in formulating the doctrine, rejected the idea of attacking civilians.

Four former instructors of the school, the core of a group known as the "Bomber Mafia", were grouped together in the Air War Plans Division to produce the two war-winning plans—AWPD-1 and AWPD-42—based on the doctrine of precision daylight bombing that guided the wartime expansion and deployment of the Army Air Forces.

In a broader sense, the strategic bombing doctrine, adapted by factors encountered during combat, was also the foundation for the final separation of the Air Force from the Army as a military service independent of and equal to the other services. In 1946 the AAF created the Air University to carry on the work and traditions of the ACTS.