President Bush is using Air Force One (search) for re-election travel more heavily than any predecessor, wringing maximum political mileage from a perk of office paid for by taxpayers.

While Democratic rival John Kerry digs into his campaign bank account to charter a plane to roam the country, Bush often travels at no cost to his campaign simply by declaring a trip "official" travel rather than "political."

Even when the White House deems a trip as political, the cost to Bush's campaign is minimal. In such instances, the campaign must only pay the government the equivalent of a comparable first-class fare for each political traveler on each leg, Federal Election Commission (search) guidelines say.

Usually, that means paying a few hundred or a few thousand dollars for the president and a handful of aides. It's a minuscule sum, compared to the $56,800-per-hour the Air Force estimates it costs to run Air Force One.

It is an advantage that Bush and other presidents before him have enjoyed. President Clinton  frequently was criticized by Republicans for his record-setting use of Air Force One in the campaign season, and Bush is exceeding Clinton's pace.

"It's really something that's abused," said Bill Allison, managing editor of the Center for Public Integrity (search), a nonprofit, government watchdog group.

"On the one hand, the president can't fly coach," Allison said. "But on the other hand, taxpayers are in essence subsidizing campaign trips, something that goes against the grain of how the political system is supposed to operate."

The White House says it is following both the law and tradition in deciding which events are official, and thus paid for by taxpayers.

"Federal election laws set forth clear guidelines as to how costs should be incurred, and consistent with decades of past practices, we strictly adhere to those guidelines," said White House spokeswoman Erin Healy.

Bush has logged more than 68,000 miles this year on Air Force One, all within the continental United States except for a quick run to Mexico in January. With rare exceptions, he confines his travels to the more than a dozen states he and Kerry are fighting hardest for, and to places where he is raising campaign money.

Of those states, Bush has made five trips to Pennsylvania, four each to Missouri, Florida and Ohio, and three to Wisconsin. He also has flown to 24 fund-raisers for himself and the Republican Party.

The White House labeled travel to fund-raisers "political." Likewise, it deemed as "political" a thank-you mixer with big donors in Georgia, his first campaign rally in Orlando, Fla., and bus tours through Michigan, Ohio, Iowa and Wisconsin, meaning his campaign paid a share of the costs.

But of the more than $203 million Bush has raised for his re-election, less than 1 percent has gone to reimbursing the government for travel costs this year.

The campaign repaid White House Airlift Operations at least $512,000 from May 2003 through April 2004, including reimbursements for political travel by Bush, Vice President Dick Cheney, first lady Laura Bush and political aides.

The reimbursements do not cover the cargo planes that shuttle the president's limousines and helicopters to every event, or travel expenses of White House advance workers who lay the groundwork for the trips.

It is difficult to say precisely what the Bush campaign is repaying the government per trip. The White House refuses to:

— Provide lists of political aides who travel with Bush and whose travels are financed by the re-election campaign; or say how many political aides go on any given trip, or even offer a range.

— Provide dollar figures on reimbursements for specific trips. Bush's re-election campaign periodically reports to the FEC lump reimbursement sums for unspecified travel.

— Say how it decides which trips are official rather than political.

An Associated Press tally of Bush's travels shows he has made at least 114 trips in the 17 months since January 2003.

Clinton flew Air Force One on 123 domestic trips between January 1995 and mid-October 1996, a period of 22 months. It was a record for re-election-related travel aboard the presidential aircraft, according to the Center for Public Integrity.