The Bomber Mafia were a close-knit group of American military men who believed that long-range heavy bomber aircraft in large numbers were able to win a war. The derogatory term "Bomber Mafia" was used before and after World War II by those in the military who did not share their belief, and who were frustrated by the insistence of the men that the heavy bomber should take a primary position in planning and funding.

The bomber mafia succeeded in their goal to have extensive bomber fleets in the US military, but they failed in their wish to achieve pinpoint targeting precision during World War II. Instead, the bomber fleets were a major factor in the general American war effort, helping to reduce the enemy fighting power, especially in Japan where they destroyed the largest cities by shifting to area incendiary bombing tactics. After the war, the 20 years of foundational work by the bomber mafia resulted in the separation of the United States Air Force from the Army to become an independent military arm. The bomber mafia's strategic doctrine, changed by war and experience, helped shape the mission of the new U.S. Air Force and its Strategic Air Command.

Many years later, in the 1960s and 1970s, a related term, "Fighter Mafia," described those within the U.S. Air Force that favored lightweight fighters good at dogfighting instead of heavy missile-firing fighters.

Developed over the years 1926–1929 at Air Corps Tactical School (ACTS) at Langley Field in Virginia, a forward-looking doctrine of daylight precision bombing was promulgated by Brigadier General William "Billy" Mitchell who advocated a greatly expanded role for the bomber force. After graduating from ACTS in 1931, Mitchell protégée Harold L. George stayed at the school to refine and teach the new bombing theory, soon recruiting as teachers his former students Haywood S. Hansell, Donald Wilson and Laurence S. Kuter as fellow bomber advocates. These four instructors, the core of US bomber advocacy, argued that an enemy's army and navy could be defeated intact due to the destruction of industrial and military targets deep within enemy-held territory.

This theory was first espoused by the Italian general Giulio Douhet, though his ideas included the strategic bombing of population centers that the American theorists eschewed. In contrast, American theorists devised a strategy of pin-point bombing that targeted enemy economies and weapon production. Though unproven, the major attraction of this type of strategic bombing doctrine was that a war was expected to be won relatively quickly, with minimal casualties, and that grinding, static trench warfare as seen in World War I could be avoided. In November 1932, the British statesman Stanley Baldwin proclaimed that "the bomber will always get through", referring to the strategic bombing of cities. The Bomber Mafia agreed with Baldwin only in that the bomber would prevail in its mission, intending for their bombing missions to be solely against military and industrial targets.

To effect this doctrine, the United States Army Air Corps would need to expend the majority of its resources in amassing a fleet of self-defending heavy bombers, and in the training and maintenance of a great many airmen to fill aircrew and ground crew positions. The ACTS officers who believed in the heavy bomber doctrine realized that any other Air Corps expenditures such as for tactical bombers and fighter aircraft would take away from the proposed large fleet of heavy bombers. Moreover, the men realized that the United States government would have to reduce funding to naval and ground forces in order to establish a great air fleet. To implement these changes, the ACTS instructors began to instill a sense in their students that a separate and independent air arm of the type described earlier by Mitchell, to be called the United States Air Force, was the way forward. As a compromise first step, the General Headquarters (GHQ) Air Force was established within the Army Air Corps in 1935, commanded by General Frank M. Andrews, a strategic bombing advocate. Andrews staffed the command with like-minded officers such as Henry H. "Hap" Arnold.

Although flawed and tested only under optimal conditions, the doctrine (originally known as the "industrial web theory") became the primary airpower strategy of the United States in the planning for World War II. Members of the "Bomber Mafia" produced the two airpower war plans (AWPD-1 and AWPD-42) that guided the wartime expansion and deployment of the Army Air Forces.

The term "Bomber Mafia" came from the sometimes bitter debates between United States Army staff and Air Corps men who observed, and argued with, the insistence by instructors and students of the ACTS that heavy bombers were the new primary weapon of war, and that a separate air arm was required to command them. For the first few years, the strongest voice at ACTS against the bomber doctrine was Captain (later General) George C. Kenney who called for the use of air power to attack enemy fighting units on the ground. He advocated the close coordination of air and ground forces, with an emphasis on medium bombers and fighter bombers. Kenney left ACTS in 1929, and heavy bomber doctrinarians filled the vacancy. The doctrine also ran counter to the theories of Billy Mitchell himself, who espoused that pursuit support was essential for daylight bombing operations.