List of military aircraft of the United States

This list of military aircraft of the United States includes prototype, pre-production, and operational types. For aircraft in service, see the List of active United States military aircraft. Prototypes are normally prefixed with "X" and are often unnamed (note that these are not the same as the experimental X-planes, which are not generally expected to go into production), while pre-production models are usually prefixed with "Y".

The United States military employs a designation and naming system to provide identifications to all aircraft types. Until 1962, the United States Army, United States Air Force (formerly Army Air Force), and United States Navy all maintained separate systems. In September 1962, these were unified into a single system heavily reflecting the Air Force method. For more complete information on the workings of this system, refer to United States Department of Defense Aerospace Vehicle Designations.

This list does not include aircraft used by the U.S. military services prior to the establishment of a numerical designation system. For these aircraft, see List of military aircraft of the United States (1909–1919). It also does not include aircraft designated under the pre-1962 United States Navy designation system. For these aircraft, see List of military aircraft of the United States (naval).

Prior to 1919, all planes flown by the Army Air Service and the Navy were referred to by the designation given to them by their manufacturer. A variety of both domestic and foreign types were operated, with the latter being the primary front-line types during the First World War.

In September 1919, the Army Air Service decided that it needed an organized designation sequence, and adopted fifteen classifications, designated by Roman numerals. Several other unnumbered designations were added later. Each designation was assigned an abbreviation, and each design a number within that abbreviation. Variants were designated by alphabetically appending letters to the design number.

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