Similar to the Army officer candidates, Air Force officer trainees exist in a gray zone with regard to rank, and their status does not directly correspond to a position of seniority or authority within the standard Air Force ranks. Typically, they are referred to or addressed as "OT," and during the first few weeks of indoctrination, are treated much the same as a new recruit. The pay for an officer trainee, however, is equal to an E-5 on the enlisted pay scale, unless the candidate previously achieved a higher enlisted rank than E-5, ., an E-7 who becomes a candidate would continue to receive E-7 pay, and so on. Once commissioned, the new officer advances to the pay rate of O-1 , unless they have at least four years of active duty service, in which case they are paid the higher O-1E rate in recognition of the prior enlisted service. Such pay continues at promotion to the next two grades ("O-2E" and "O-3E"), but is discontinued at the grade of O-4 .
At the height of the Vietnam War , Infantry OCS produced 7,000 officers annually from five student battalions, all located at Ft. Benning. Also, during the war, a female OCS was once again established; it was stood up at Fort McClellan, Alabama, as part of the WAC Center and School. Other OCS programs were located at Fort Gordon , Georgia (Signal Corps); Fort Sill, Oklahoma (Artillery), Fort Lee, Virginia (Quarter Master),Fort Eustis, Virginia (Transportation), Fort Knox, Kentucky (Armor), Fort Belvoir, Virginia (Engineer) and Aberdeen Proving Ground, Maryland (Ordnance). In April 1973, a branch immaterial OCS was established at Fort Benning, ending the Infantry and Field Artillery based courses. In 1976, with the end of the gender separate Army, the women's OCS was merged with the branch immaterial male course, creating a program very similar to the modern OCS. The United States Military Academy at West Point, New York , also admitted its first female cadets in 1976. However, due to the length of instruction there (4 years), the newly gender-integrated Officer Candidate School had the distinction of commissioning a female second lieutenant before USMA.