Enlist in the Air Force: The actual process of joining the Air Force is fairly simple, but there are some requirements and evaluations, such as an aptitude test and a physical, that you must pass before joining. You must be between 17 and 27 years of age, a U.S. citizen or legal, permanent resident and have a high school diploma.Air Force Reserve: The Air Force Reserve is an exciting, vibrant part of the nation's defense. It offers similar benefits afforded to those on active duty, with one major addition: the benefit of time.Air National Guard: The Air National Guard trains part time to assist in domestic disasters and international conflicts.Air Force Academy: The Air Force Academy is both a military organization and a university. Much of the Academy is set up like most other Air Force bases.ROTC: Take the classes you want at the college you want to attend. Air Force ROTC classes complement your academic major.