Mitchell, William (1879–1936), a United States army officer and aviator. “Billy” Mitchell was one of the first to recognize the future military role of the airplane. After World War I, he argued that air power would be essential for waging war and favored an air force independent of the army and navy. He warned of the chance of a Japanese air attack on Pearl Harbor. Mitchell resigned from the army after a court-martial in 1925 convicted him of publicly criticizing armed forces officials.

Mitchell was born in Nice, France, the son of American parents. He grew up in Milwaukee, Wisconsin, and attended Racine College and George Washington University. In 1898 he enlisted in the army at the outbreak of the Spanish-American War, and soon after he received a commission in the Signal Corps. He saw action in Cuba and the Philippines. Mitchell learned to fly in 1916, becoming one of the nation's best pilots.

In World War I, Mitchell commanded various air squadrons and was the first United States officer to fly over enemy lines. He commanded the largest air attack in the war—1,481 planes—during the St. Mihiel offensive of September, 1918. In October he was made a brigadier general. In 1919 Mitchell was made director of military aeronautics and assistant chief of the Air Service.

In widely publicized tests in 1921, Mitchell's bombers sank obsolete battleships, and he declared that battleships had no future. His demands for aviation expansion were ignored, however, and in 1924 he was demoted to colonel for his increasingly critical statements about his superiors and the lack of preparedness of the tiny Air Service. After the wreck of the dirigible Shenandoah, Mitchell accused the army and navy of “incompetency, criminal negligence, and almost treasonable administration of the national defense.” He was then court-martialed. He was convicted in December, 1925, and sentenced to a five-year suspension from duty without pay.

Mitchell resigned from the army in 1926, but continued his fight for air power. He wrote Our Air Force (1921); Winged Defense (1925); and Skyways (1930). In 1946 Mitchell was posthumously awarded a special medal by Congress, and in 1947 he was promoted to major general, retroactive to the date of his death.