Just weeks after Citigroup averted total collapse with a $45 billion shot in the arm of taxpayer cash, the bank jetted its former CEO and his family on one of its corporate jets to a posh Mexican resort for New Year’s, The Post has learned.

Sandy Weill, 75, hopped aboard the tanking bank’s Bombardier BD 700 Global Express on Dec. 26 with his wife, Joan, daughter Jessica, her husband and their children. They flew from Westchester County Airport to the Los Cabos shore region in sunny Baja, according to aviation records and sources familiar with the trip.

The holiday jaunt came the same week that Citigroup – which lost $28.2 billion over the last five quarters and cut 75,000 jobs globally in 2008 – agreed to curtail runaway corporate expenses as part of a deal to get the massive influx of federal money.

The new belt-tightening policy went into effect on Dec. 31, while the jet was parked at the Los Cabos airport.

The family stayed through Jan. 3 at the ultra-expensive One & Only Palmilla in San José del Cabo – where a four-bedroom suite costs $12,000 a night. It’s the same beachfront resort favored by high-wattage stars like Jennifer Aniston and John Travolta and is where Eli Manning got married in April.

Weill, among the richest men in the country, was Citigroup’s CEO until 2003 and its chairman until 2006. He played a key role in forging the company into the behemoth that toppled under its own weight in the recent credit crisis.

Although he stepped down in 2006, he remains an adviser to the company and was to keep access to corporate jets until 2016 as part of a blockbuster retirement package he worked out with the bank.

But with the recent collapse, Weill agreed last year to give up most of his perks – including access to company planes – as of April 2009.

The $45 million Bombardier Global Express is part of a company fleet of four jets and one helicopter reserved for use by 12 to 15 Citigroup executives.

A source close to Weill confirmed he and his family used the plane over the holidays.

Weill could have repaid some or all of the plane trip’s costs. An SEC filing says Weill has to compensate the company “based on a cost-per-flight-hour charge developed by a nationally recognized and independent service which reflects the operating costs of the aircraft.”

“He paid what he agreed to in the contract, which he strictly adheres to,” the source said.

News of the taxpayer-aided bank using its corporate aircraft for a deluxe personal getaway comes a week after The Post reported that Citigroup was set to take delivery on a new $50 million corporate jet, a French-built Dassault Falcon 7X. A day later, the bank reluctantly scrapped the purchase under pressure from President Obama and Congress.

Citigroup declined to comment on the trip.

“For security reasons, we don’t comment on the use of company aircraft,” said Shannon Bell, a spokeswoman for the bank in New York.

Industry experts estimate that chartering a plane for such a nine-day trip would cost anywhere from $60,000 to $80,000, including fuel, maintenance, insurance and the salaries of a three-person flight crew.

Additionally, Los Cabos’ plane parking fees for a week would add another $2,000. Putting up two pilots and a flight attendant in a mid-range Los Cabos-area hotel would cost around $300 apiece a night, or $7,200 for the week. Giving each a minimum of $50 a day for meals would cost another $1,350.

That would bring the total cost to between $70,550 and $90,550.

Despite taking a hit in the recent economic collapse, Weill remains one of the richest men in America with an estimated net worth of $1.3 billion in 2008, according to Forbes magazine. That’s down from $1.5 billion in 2006.

In addition to use of the plane, Weill has been receiving roughly $3 million in perks from Citigroup since he retired – including consulting fees, health insurance, pension, tax compensation, rental costs for his swanky Midtown office and use of company cars.

Joining Weill on the Los Cabos trip were his millionaire daughter Jessica Bibliowicz, 49, CEO of National Financial Partners, a money-management firm that caters to the super-rich. Also aboard was her husband, Natan Bibliowicz, a high-profile Manhattan architect whose company handles multimillion-dollar projects, including the renovation of Carnegie Hall.

The Global Express in which Weill and his family flew is made by Bombardier Aerospace in Canada and retails for about $45 million. It is designed to fly at high speeds and for long distances without refueling.

Seating up to 18 passengers, the interior features a full bar and fine-wine selection, along with “$13,000 carpets, pillows that were made from Hermes scarves, Baccarat Crystal glassware and Cristofle sterling silver flatware,” said a former crew member.

Weill’s party departed from an exclusive terminal for private planes at the Westchester County Airport that resembles a five-star hotel lobby, complete with a doorman, grand piano and work stations outfitted with Macintosh computers.

The terminal also has a “quiet room” for pilots and a Starbucks. Richard Gere was spotted there last week, ordering a cappuccino after his private jet landed.

Additional reporting by Cynthia R. Fagen and Isabel Vincent

brad.hamilton@nypost.com