William Lendrum "Billy" Mitchell (December 29, 1879 – February 19, 1936) was a United States Army general who is regarded as the father of the United States Air Force.

Mitchell served in France during World War I and, by the conflict's end, commanded all American air combat units in that country. After the war, he was appointed deputy director of the Air Service and began advocating increased investment in air power, believing that this would prove vital in future wars. He argued particularly for the ability of bombers to sink battleships and organized a series of bombing runs against stationary ships designed to test the idea.