In the year, 1942, during World War II when new torpedo boats where being created a letter was written to Walt Disney asking him to design a new insignia for the United States Military. These new boats were known as Mosquito boats, so Walt Disney decided to create a insignia with a mosquito wearing a tar hat and holding a torpedo between his legs (as seen in the above picture). The military loved Walt Disney's creation and wanted him to create more. Later, Walt Disney created several designs for a variety of vehicles. He created designs for tanks, minesweepers, bombers, and fighter planes. Walt Disney's designs became extremely popular, and soon enough the Army and Navy requested for an insignia of their own.
The video shown below shows you how an United States Air Force insignia was made.