Aircraft
      by Nation
      United States
      Military since 1962
      Observation:  The
      "O" for Observation designation typically designates aircraft
      used in observation, forward air controller, or light-attack
      missions.  The Observation designation was resurrected in 1962 having
      been discontinued by the Air Force in 1942.
       The "V" in the "OV" designation
      indicates an STOL aircraft.