"Taxpayers will pickup much of the cost of the trip, including the largest share of the $35,000 per hour cost of operating Air Force One and thousands of dollars per hour for additional costs to provide security and other support. In addition to the cost of Air Force One, a support staff that includes senior aides, the Bush physician and Secret Service agents often accompanies the president. A large Air Force cargo plane carrying communications equipment, more support staff, an armored limousine and if needed, his helicopter, also travels on presidential trips.
All of it adds up.
Congress' independent General Accounting Office, in a 2000 study, calculated that it cost $2.2 million for Clinton to travel from Washington, D.C., to Vancouver, B.C., for a two-day economic summit in 1997. That study also estimated that Air Force One cost $35,000 per hour to operate although on some trips it went as high as $56,000 an hour."
http://seattlepi.nwsource.com/national/178018_bush16.html