(Alex airmails one to us from the Atsugi NAF, Japan.)  The mission of the C-2A Greyhound is C.O.D.--the O.D. stands for "onboard delivery", of things like jet engines & other equipment, to the C, this type of ship
[DOC] [TLE] Kitty Hawk II (CVA-63) - NHHC - Navy [PAR] 7 Dec 1962: LT(JG) Ray Barnes, VA-113, became the ship's first jet centurion by 
.... A Kaman UH-2 Seasprite planeguard, HC-1 Det 1, Unit C, Kitty Hawk and a 
Sikorsky .... made the first Greyhound carrier onboard delivery (COD) in the 
combat zone on ... 19-21 Jan 1967: Heavy attacks with other naval aircraft struck 
enemy...