Each of the Marine Corps 's two observation squadrons ( designated VMO ) had 18 aircraft -- nine OV - 10As and nine OV - 10Ds night observation aircraft .
The OV - 10 was first acquired by the U.S. Marine Corps .
Each of the U.S. Marine Corps   's two observation squadrons ( designated VMO ) had 18 aircraft -- nine OV - 10As and nine OV - 10Ds night observation aircraft .
The OV - 10 was first acquired by the U.S. Marine Corps .