How is mail routed to Navy ships and Marine Corps units?
After processing at the Military Gateway, mail for Navy and Marine forces on board ships is flown to a Fleet Mail Center such as the one in Bahrain or Sigonella (Italy). FPO mail is sorted and transported to the individual ships by various means (often by small aircraft called Carrier Onboard Delivery (COD), to an aircraft carrier), often in conjunction with a supply mission.
