The Air Force is going through the toughest recruiting environment in “well over two decades,” and its current recruiting class is on the verge of missing its goal for the first time this century.

Military branches across the board have experienced difficulties in signing up new recruits in recent years, with both short- and long-term factors contributing to the predicament. The Air Force is 4,500 recruits behind where it should be in a different year, Maj. Gen. Ed Thomas, the Air Force Recruiting Service commander, told the Washington Examiner in an interview Tuesday.