PHILADELPHIA – US Airways Group Inc. received court approval Thursday to extend a crucial agreement with the federal government that helps provide the financing the airline needs to reorganize and emerge from Chapter 11 bankruptcy this summer.

The agreement with the U.S. Air Transportation Stabilization Board lets the airline use the cash it has on hand through June 30. US Airways expects to find $100 million in additional financing or cost savings by next week to get through the winter, when business is slowest.

“This long-term agreement is a huge boost for our customers,” chief executive officer Bruce R. Lakefield said in a statement. “Our customers should book us with confidence, knowing that we have sufficient cash to operate as well as implement the many changes that are under way.”

US Airways shares rose 13 cents, or 12 percent, to $1.21 in over-the-counter trading.

The agreement with the federal board, approved by U.S. Bankruptcy Court Judge Stephen Mitchell in Alexandria, Va., is dependent on US Airways’ maintaining weekly minimum cash balances. The board, created by Congress after the Sept. 11, 2001, attacks to help the industry recover, guaranteed a $1 billion loan that US Airways received when it emerged in March 2003 from a first bankruptcy.

According to the board, US Airways still owes $718 million on the loan, $645 million of which is guaranteed by the board. US Airways said it had $823 million in cash and $1.5 billion in total current assets as of Nov. 30, in its most recent financial report to the Bankruptcy Court.

The extension comes after the airline extracted $950 million in annual savings from its labor unions. Most unions reluctantly agreed to accept cuts in pay and benefits. Last week, Mitchell imposed an estimated $263 million in concessions on the International Association of Machinists, which represents US Airways mechanics and baggage handlers, when the union failed to reach tentative agreements covering all its members.

IAM members are voting this week and next on whether to accept the company’s last contract offer. Analysts said the agreement would help assure some travel agents and customers that US Airways will be around in coming months.

But the airline’s service recently – and particularly the plethora of canceled flights and lost bags that Philadelphia passengers experienced over the Christmas weekend – has hurt the company badly, and its situation remains precarious, they said.

“US Airways is making good progress in achieving cost reductions and reaching agreement with key stakeholders,” said Philip Baggaley, Standard & Poor’s Corp.’s airline credit analyst. But, he said, the airline “could still be grounded if it encounters serious labor unrest, or if the airline industry is hurt severely by a fuel price spike or terrorism, or if the company cannot attract outside investment and credit to finance emergence from Chapter 11.”

US Airways also said this week that seven senior executives had recently resigned or retired. Ben Baldanza, senior vice president of marketing and planning, quit to become chief executive of low-fare carrier Spirit Airlines Inc., which serves Atlantic City, N.J.

Baldanza’s replacement is Bruce Ashby, who had been vice president of alliances and president of US Airways Express, the company’s commuter subsidiary.

Ashby, in a memo to other marketing employees Wednesday, wrote, “There is much to be optimistic about. We have turned the corner with our labor groups, and we are now engaged together in the competitive fight that the company faces. We are leaner, tougher, and ready to win.”