The next time airfare seems too expensive, consider the cost of Air Force One.

The plane that is used to carry the president, which is typically a Boeing 747, costs the Air Force $179,750 per hour to operate, according to a new Congressional Research Service report. Military planes are used for security and because of special equipment on board.

Costs for each trip are even higher when factoring in the passenger and cargo aircraft that often accompany the president's plane, although those figures weren't specified in the eight-page report.

Taxpayers cover the cost of trips for official business, and campaign organizations reimburse the government for whatever portion of a trip is deemed political.

"It is unclear how the White House designates travel that is not directly related to a governmental or political function because of traditional reluctance to address this matter," the report said. Vacations count as official travel.

Information about the cost of presidential flights is scarce, according to the report. But earlier studies from Congress and the Government Accountability Office offer a glimpse of the cost of several major trips in the past.

For example, a European trip in 1989 cost the Air Force $1 million and a trip to Hawaii in 1990 cost $1.5 million, according to a 1992 report from a House committee on the civil service. The figures represented just operational costs for the aircraft – without related expenses such as food and lodging.

Extra costs add up quickly. These related costs for presidential trips in 1998 totaled $42.8 million for Africa, $10.5 million for Chile and $18.8 million for China, according to a GAO report.

Comparable information wasn't available for more recent trips, the Congressional Research Service report says.