Department of Defense Directive-Type Memorandum (DTM) 08-046: Directive-Type Memorandum (DTM) 08-046 - Precedence for Official and Unofficial Travel on Government Aircraft [open pdf - 85KB]
"This DTM revises outdated DoD policy contained in Reference (a) regarding required use travel by senior DoD officials on U.S. Government aircraft. This DTM is effective immediately and remains in effect until approval of a revision to Reference (a), which should be completed within 60 days. This DTM applies to OSD, the Military Departments, the Office of the Chairman of the Joint Chiefs of Staff and the Joint Staff, the Chiefs of the Military Services, the Combatant Commands, and all other organizational entities within the Department of Defense."
DoD Directive-Type Memorandum 08-046; DoDDTM 08-046