WASHINGTON – Bill Clinton’s foundation has spent more than $50 million on travel expenses since 2003, an analysis of the non-profit’s tax forms reveal.

The web of foundations run by the former president spent an eye-opening $12.1 million on travel in 2011 alone, according to an internal audit conducted by foundation accountants. That’s enough to by 12,000 air tickets costing $1,000 each, or 33 air tickets each day of the year.

That overall figure includes travel costs for the William J. Clinton Foundation (to which Hillary and Chelsea are now attached) of $4.2 million on travel in 2011, the most recent year where figures are available.

The Clinton Global Health Initiative spent another $730,000 on travel, while the Clinton Health Action Initiative (CHAI) spent $7.2 million on travel.

CHAI also spent $2.9 million on meetings and training, according to the report, conducted by the Little Rock, Ark. Accounting firm BDK CPA’s and Advisors. All three entities have global reach, while CHAI has the most staff.

It’s impossible to discern from tax filings how the total travel costs were reached, although the former president is known to rack up his personal miles on private jets.

Wealthy businessman John Catsimatitis has lent aircraft to Clinton and to the foundation multiple times for travel, including Clinton’s recent trip to Africa along with daughter, Chelsea.

Clinton sometimes uses Catsimatitis’ Boeing 727, opting on other flights to use a smaller Gulfstream jet.

“I don’t think it’s necessarily their go-to plane, because the 727 is a pretty big plane. It all depends where they’re going and what they’re doing,” said a Catsimatitis spokesman.

Sometimes Clinton uses the plane at a discount rate for the foundation, and sometimes Catsimatitis donates the flight time to the charitable foundation, which has a variety of programs to improve global health and improve conditions in Haiti and other far-flung locales.

According to previously undisclosed data provided by the Clinton Foundation, presidential trips accounted for 13 percent of the 2010 travel budget and 10 percent of the 2011 travel budget.

That puts Bill Clinton’s single-year travel tab for 2011 at more than $1 million. A foundation official wouldn’t say how many presidential trips occurred in that time frame.

The remaining travel paid for an array of foundation travel, with nearly 60 percent soaked up by the health access initiative, and about 5 percent going to the Clinton global health initiative, including flying students to attend Clinton Global Initiative University.

A Climate Change Initiative took up 12 percent of travel in 2010 and 11 percent in 2011, although the program accounts for a much smaller fraction of foundation revenues. A foundation official said that’s because the program employs many overseas staff and domestic staff doing transcontinental travel.

Clinton made reference to foundation overhead in an “open letter” posted on his foundation’s web site – mentioning an outside review that called for “stronger management staff” and blaming his own efforts to keep costs down.

“The review told us that my passion to keep overhead costs down – at about a low

8 percent for most of the last decade, rising only to above 11 percent in 2012 as we invested to support our growth – had gone on too long and that the Foundation needed better coordination without dampening the entrepreneurial spirit that infuses all our initiatives,” he wrote.

The sky-high travel costs come after a report revealed some of the foundation’s high-flying ways, including letting actress Natalie Portman fly first class with her pooch to a foundation event.