Modifications made for the military configuration included fore-and-aft seating for a pilot and observer, instead of the six seats of the civilian version; installation of view panels in the doors (for improved ground observation); installation of flame-retardant foam in the wing-mounted fuel tanks (slightly increasing weight, and reducing maximum fuel capacity by 3%); installation of military, rather than civilian, communication and navigation equipment and antennas; removal of propeller spinners; increased gross weight (5,400 lb vs. 4,400 lb in civilian version), with component strengthening as required to support the increase; and removal of interior upholstery.

Performance (especially at cruising altitudes) was degraded due to the added antennas and significant weight increase, but was considered sufficient for the anticipated low-level operation.

These aircraft were later transferred to Strike Fighter Squadron 125 (VFA-125), the F/A-18 Hornet FRS at NAS Lemoore, in 1986 for use in the same range control role.

[6] Two O-2As were used at Laguna Army Airfield, Arizona as part of testing programs carried out by the Yuma Proving Ground.

Near the end of the war in 1990, the rebels' acquisition of SA-7 missiles resulted in the loss of two O-2As, while another was destroyed by mortar fire, and two more were lost in crashes.

[8] In the mid-1970s, the California Department of Forestry and Fire Protection, or CAL FIRE, found that the contractor-owned air attack aircraft, mostly single-engine Cessna 182s and Cessna 210s, did not provide the airspeed and safety needed for the department's new air tanker program.

A crew of California Conservation Corps (CCC) members under the supervision of a CDF Battalion Chief, who was an FAA Certificated Mechanic with Inspection Authorization (IA), reassembled the aircraft.