The Air Force divides criminal offenses into five categories:
Category 1 offenses are considered the most serious (felonies), and category 5 offenses are the most minor. Applicants with one or more convictions or adverse adjudications from category 1, 2, or 3 offenses require a waiver. Those with two or more convictions or adverse adjudications in the past three years, or three or more convictions or adverse adjudications in a lifetime for a category 4 offense also require a waiver. Air Force applicants with six or more convictions or adverse adjudications in any 356 day period within the past three years from a category 5 offense also require a waiver.
Applicants may not enlist as an alternative to criminal prosecution, indictment, incarceration, parole, probation, or other punitive sentence. They are ineligible for enlistment until the original assigned sentence would have been completed.
In most cases, substance abuse of any kind (drugs, alcohol) is a disqualifying factor.