United Airlines yesterday launched a major effort to persuade customers, employees and suppliers not to abandon the company after it filed for bankruptcy and acknowledged that its losses had grown much worse in recent months.

The filing in federal bankruptcy court in Chicago by UAL Corp., the airline's parent company, listed $22.8 billion in assets and $21.2 billion in liabilities, making it the largest airline bankruptcy in U.S. history.

United is the nation's second-largest airline, with 80,000 workers who collectively own 55 percent of the company and now are likely to lose their entire stake.

The airline announced immediate pay cuts for managers and said it hopes to renegotiate its debt, win major concessions from its unions and emerge within 18 months as a profitable, though probably smaller, carrier.

But that will depend on its ability to maintain and even increase revenue and keep its suppliers on board. During court proceedings yesterday, UAL lawyer James Sprayregen said the carrier expects to lose $20 million to $22 million a day in December and $10 million to $15 million a day in January, compared with daily losses of $7 million to $8 million at the end of September.

UAL chairman and chief executive Glenn F. Tilton spent the day greeting passengers at Chicago's O'Hare International Airport, rallying employees, monitoring bankruptcy court proceedings and giving media interviews. Top executives visited other key airports.

"We're going to perceive this not as a Chapter 11, but as a Chapter 1. It's a new beginning for United," Tilton said in an interview.

Today many newspapers will carry full-page advertisements conveying that theme: "You will feel the new energy and the new optimism. You will feel the new beginning."

Meanwhile, the airline, which is trying to extract large concessions from its unions, announced pay cuts for 10,500 United officers and managers. Officers' salaries will be reduced by 11 percent and managers by between 2.8 percent and 10 percent, depending on their salaries.

Tilton's $950,000 salary will be cut 11 percent, but he plans to keep the $3 million bonus that he received when he joined the airline this past Labor Day weekend. He also has stock options for 1.15 million shares, something that will not be affected by the cuts.

The pilots had agreed to 18 percent pay cuts, as part of the $5.2 billion in labor concessions that United negotiated in an effort to win a $1.8 billion federal loan guarantee. The leaders of the International Association of Machinists negotiated a 7 percent cut for mechanics, but union members have not approved it. The cuts were contingent on federal approval of the loan guarantee.

But the government rejected the airline's application last Wednesday, causing United to file for bankruptcy protection from its creditors. Sources close to the company said United will now need more cuts to emerge from bankruptcy.

"The pilots are going to want to work in a collaborative fashion to keep the company out of Chapter 7 and to get out of the current situation as fast as possible, even if that means something different from what was agreed to before. But to discuss specific numbers before we've been to the bargaining table doesn't make sense," said Paul Whiteford, head of United's pilots union. He was referring to Chapter 7 of the federal bankruptcy code, under which companies are liquidated.

Joe Tiberi, a spokesman for machinists union, declined to comment on concessions.

United has lined up $1.5 billion in financing to enable it to run, at least for a while, during the bankruptcy reorganization process. At the hearing, Eugene R. Wedoff, chief judge at the U.S. Bankruptcy Court of Northern District of Illinois, gave United permission to use about $800 million of the financing, which will become available in 11 days. United received loans from J.P. Morgan Chase & Co., Citigroup Inc., Bank One Corp. and CIT Group Inc. Yesterday, Deutsche Lufthansa AG said it was considering offering financial assistance to United as long it was "secured," said Lutfhansa spokesman Tom Tripp. Lufthansa and United are the biggest members of the Star Alliance of several airlines from around the world.

United said it has $1.4 billion in cash, of which $600 million cannot be easily accessed. At the end of September, United had $2 billion in cash, of which $340 million was restricted.

The next bankruptcy court hearing is scheduled for Dec. 30.

United's top 20 creditors have scheduled a meeting for Friday.

"This is liable to be a long, contentious and potentially difficult reorganization," said aviation analyst Philip Baggaley of Standard & Poor's Corp. One reason, said Baggaley, is that the airline failed to arrange for major cost cuts and secure additional financing before it filed.

In contrast, when Arlington-based US Airways filed for bankruptcy in August, it had obtained most of its $900 million in concessions from its employees and had a conditional loan guarantee from the federal government for $900 million. In addition, it had $500 million lined up in financing from outside lenders.

United has $1.5 billion in financing but no labor concessions and no federal loan guarantee. With the airline losing at least $20 million daily, its financing could be used up quickly, especially if the nation goes to war with Iraq or if there is an extremely cold winter, causing fuel prices to surge.

UAL has had nine straight quarterly losses, including a loss of $1.7 billion in the first three quarters of this year. It lost $2.1 billion in 2001. Profit started falling in 2000 as the carrier battled unions over new contracts and a proposed $12.5 billion purchase of US Airways. The government struck down the deal, saying it was anti-competitive.

Crucial to United's long-term survival will be its ability to cut costs and raise money. Analysts expect the airline to reduce the number of flights it makes between some cities and to sell some routes altogether.

A source close to United said flight reductions are likely in the coming months. Tilton agreed that there will be some reductions in operations, but he said they won't be made "anytime soon." Over the next few months, Tilton said, the airline will review its operations and routes and either downsize or eliminate those that aren't profitable.

At least one airline chief executive, Continental Airlines' Gordon M. Bethune, has indicated he would be interested in acquiring some of United's assets.

Tilton said he has no plans to sell slots at Dulles International Airport, where United is the largest airline. "Dulles continues to be a very important hub for us. We're very pleased with the operations there," he said.

He also said United plans to reapply for a federal loan guarantees after the airline cuts more costs and is close to emerging from bankruptcy.

Tilton said he was not surprised that the Air Transportation Stabilization Board rejected the application. He knew it could be tough to get approval, he said, and thus had begun talks with bankruptcy experts. Kirkland & Ellis is United's bankruptcy attorney, and Rothschild Inc. is providing restructuring advice.

Tilton said he thinks a major United misstep was its answer to a question on how it would increase its revenue if it faced increased competition from low-cost carriers Southwest Airlines and JetBlue Airways. United responded that it would use the federal loan guarantees to help it fight off competition.

After the bankruptcy filing at 6 a.m. yesterday, Tilton rushed to O'Hare, hugging passengers and shaking hands, encouraging them to continue to fly on his airline and promising they would not see any major disruptions in service.

Tilton said he plans to lead the effort to keep customers flying. "This is the most appropriate place for me to be," said Tilton, who has spent much of his career in marketing before becoming vice chairman of ChevronTexaco Corp. "It's about the customer, the customer, the customer. I'm the number one salesman for this company."

Tilton's earlier career gave him experience with bankruptcy. In 1987, Tilton was a top manager at Texaco when the oil company reorganized. But this bankruptcy is different from Texaco's, he said, because United will have to change dramatically by reducing costs and streamlining operations.

Some industry experts are skeptical that someone from outside the industry will understand the business well enough to be able to resuscitate the airline, but others say an outsider could bring a fresh perspective.

Another critical element of the reorganization will be the employees, who gave up millions of dollars in 1994 in exchange for 55 percent ownership of the airline. Now their shares, which hit a high of about $100 in 1997, are worthless.

Staff writers Kari Lydersen and Jonathan Finer contributed to this report.