Aerial military divisions that emerged under the aegis of the army in the early twentieth century and separated as a department in 1947. The army navy and marines also have aviation divisions, responding to technological possibilities of air flight as well as changing warfare. The air force has become central to modern military action from Vietnam to the Gulf War; its pilots have a glamour among military personnel— President George Bush and Senator/Presidential candidate John McCain were both pilots, albeit for the navy. The Air Force academy outside Colorado Springs, was founded in 1954. Personnel on active duty numbered 363,479 in 1998, 18 percent of whom were women. See Pentagon.