Historical clue formulations

• Pres. title — 2009-12-06
• #1 on Air Force One — 2006-03-24
• President, militarily speaking: Abbr. — 2005-05-20
• Air Force One passenger: Abbr. — 1999-10-09
• Pres. Clinton, to the Joint Chiefs — 1999-09-26
• The Pres., militarily speaking — 1999-01-16