A F/A-18B 'Hornet' of the VFA-106 squadron. U.S. Navy Aircraft tail codes are used to organize an aircraft in Carrier Air Wings. In Carrier Air Wing tail codes, the first letter denotes which fleet the Air Wing deploys from; A for Atlantic Fleet and N for Pacific Fleet. There are exceptions to this rule, as Fleet Replacement Squadrons for carrier based aircraft use the CVW style tail codes for the side of the country the unit is based from AD signifying a unit based in the east: Naval Air Station Oceana, Virginia.