NEW YORK (CNN/Money) - A federal bankruptcy judge approved $75 million in emergency financing Monday to allow bankrupt US Airways Group Inc. to restructure its finances and maintain operations through September.

US Airways filed for bankruptcy Sunday, saying it will continue to operate while it tries to restructure its finances and emerge from protection early next year.

While the company vowed that its customers would not be affected by the filing, shareholders are likely to have their holdings wiped out by the filing. Shares of US Air (U: Research, Estimates) did not trade Monday on the New York Stock Exchange, which said trading on the exchange would remain halted while it completes an evaluation of how the stock complies or no longer complies with listing requirements. In both pre-market and after-market trading on Instinet, shares were off $1.95, or 80 percent, to 50 cents.

Other airline stocks retreated Monday, although airline analysts suggested the filing could be good news for other carriers as it gave airlines more leverage in union negotiations on new contracts. But concerns that UAL Corp. (UAL: down $1.40 to $3.80, Research, Estimates), parent of No. 2 United Airlines, could be the next to file for bankruptcy protection sent those shares sharply lower as well.

The filing is not a shock. US Airways was in financial trouble before Sept. 11 and took a harder financial hit from the attack than other major carriers. It warned in May in a Securities and Exchange Commission filing that bankruptcy was a possibility.

The filing was made Sunday in the U.S. Bankruptcy Court for the Eastern District of Virginia, which approved a series of temporary, or "bridge," relief orders, including continuing US Airways' Dividend Miles frequent flier program, paying employees, paying vendors, honoring obligations to other airlines, and maintaining bank accounts.

Monday the court approved $500 million in debtor financing from a group led by Credit Suisse First Boston and Bank of America. It also ended leases on 33 aircraft no longer used by the carrier. Company attorneys also revealed that top management at the carrier would be taking 20 percent pay cuts.

US Air also announced Sunday it will receive a $200 million equity investment from Texas Pacific Group that will give the firm a 38 percent stake in US Airways upon its emergence from Chapter 11 protection.

"In the face of an uncertain and trying time for the industry, we have been impressed with the major strides taken by US Airways' management and employees to significantly improve the competitiveness of the airline," said Richard P. Schifter, a Texas Pacific partner, in a statement released by US Air. "Our capital and industry experience can contribute to the company's prompt emergence and long-term prosperity."

According to its bankruptcy filing, US Air's largest unsecured creditors include bankers J.P. Morgan Chase & Co. (JPM: Research, Estimates) at $71.4 million, and Wilmington Trust Co. (WL: Research, Estimates) at just under $50 million, as well as information technology service company Electronic Data Systems Corp. (EDS: Research, Estimates) at $46.9 million.

EDS issued a statement saying its total exposure to US Air's bankruptcy filing is about $140 million, but that it is in discussions with US Air about its contracts and that it expects to continue to work for the airline and to be paid for its services. It also said it does not believe that, "restructuring of the IT services agreement, if any, to be material to its (EDS') results of operations or financial position."

US Air is expecting a $1 billion collateralized loan backed by a federal guarantee that has been conditionally approved by the Air Transportation Stabilization Board, provided the company is able to get cost-cutting accords with its unionized employees.

US Airways has been in the process of negotiating lower wage agreements with its unions, and had already won concessions from the pilots and flight attendants. The International Association of Machinists has agreed to present a company proposal to rank and file for consideration.

"Our members will not give up on US Airways, and neither should anyone else," IAM General Vice President Robert Roach Jr. said. "We believe US Airways can successfully restructure while it continues to serve the traveling public and provide employment for our members."

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The only significant union that has yet to agree to either concessions or a rank and file vote is the Communications Workers of America, which represents its customer service workers. The union said it is committed to continued negotiations with the company. Talks were scheduled for Monday, the union said.

The company has agreed to union representation on its board of directors in return for concessions. It is also vowing not to seek to use bankruptcy court powers to void labor contracts.

"We recognize the impact the sacrifices they are making will have on them and their families," CEO David Siegel said. "In exchange for their participation, we have committed that this will be a labor-friendly Chapter 11 reorganization, in which we will honor new agreements that have been ratified, and provide labor a voice in the company's governance."

US Airways says it expects the court-supervised restructuring will be accomplished on a "fast track" basis, and that it will emerge from Chapter 11 protection in the first quarter of 2003. In its petition, US Airways says it listed assets of $7.81 billion and liabilities of about $7.83 billion.

US Airways has tried to cut lease rates on some of its 311 planes, but was having trouble, Senior Vice President Chris Chiames said.

"We've been putting off payments on aircraft for going on two months now," he told reporters. "The financial condition of the airline was such that it was unsustainable to continue to operate with such a high cost involving older aircraft that have high lease rates and those kinds of things."

The airline was already in severe financial trouble and in need of restructuring before the Sept. 11 terrorist attack. The carrier's executives admitted that it was in a difficult niche of the market, not large enough to be a major national carrier, not small enough to compete as a low-cost carrier.

It has no alliance partners with which to share customers, and it has had only one profitable quarter since June 1999, as it posted losses while competitors were still recording strong earnings.

It tried to sell itself to UAL for $4.3 billion, or $60 a share, in a deal announced in early 2000 that would have been the industry's largest merger. But after federal antitrust regulators blocked that purchase, it announced a restructuring plan that called for the use of smaller planes and a lower wage scale for union members.

Before it had a chance to move on that plan it was hit harder than any other carrier by the Sept. 11 terrorist attack. Its key hub at Reagan National Airport in Washington, D.C., stayed closed weeks after other airports opened, and it saw a loss in business on its key Washington-New York shuttle to Amtrak's new high-speed rail service, which some fliers felt was more convenient due to the airlines' tougher check-in procedures.

The airline lost $17.35 a share last year, and $7.86 a share in the first six months of this year. Analysts surveyed by earnings tracker First Call were expecting second-half losses of $6.27 a share, and 2003 losses of $6.24 a share. The airline said that its prospects should improve with the advantages of a bankruptcy filing.

"We feel that we're in a good position, that this will make us a stronger airline," Chiames said. "We'll be able to clean up our financial status with regard to balance sheets and aircraft that are too expensive to fly, and emerge as a stronger, more viable competitor on the East Coast, where most of our flights are operating."

After the bankruptcy announcement, brokerage firm Merrill Lynch's airline analyst, Michael Linenberg, said his firm would drop coverage of the bankrupt air carrier.  

-- CNN Correspondent Patty Davis contributed to this report.