Bankruptcy provides time, no guarantees.

United Airlines chief James Goodwin and his top executives were huddling in his second-floor office when a secretary burst in with the news: An American Airlines jet had flown into the World Trade Center.

Andy Studdert locked eyes with Goodwin and dashed out the door. United's stocky chief operating officer sprinted the length of a football field through the airline's sprawling headquarters near O'Hare International Airport. He ducked into a covered walkway between buildings, then bounded up a set of stairs, two at a time, to the operations center.

"Confirm American into World Trade Center," Studdert barked, his barrel chest heaving.

But the dispatchers, keeping track of air traffic around the globe, had other concerns. "We can't find Flight 175," one of them shouted.

Another rushed across the room with word that a flight attendant aboard 175 had called a maintenance hot line to report a bloody hijacking.

Sensing disbelief among his employees, who had undergone a crisis-training exercise just 10 days before, Studdert told them, "This is not a drill."

As they helplessly stood by, Flight 175 hit the trade center. United Flight 93, bound from Newark, N.J., to San Francisco, was missing too.

With that, Studdert gave an order he had never delivered, not even in doomsday drills: "Ground the fleet!"

In the span of a single, bright summer morning, the nation arrived at a horrific new destination _ a world of terrorism, fear and uncertainty.

Even as the airline pulled together in the crisis, the events of Sept. 11 laid bare its fragile financial state, and massive losses pushed it into bankruptcy. Only now, as the summer travel season approaches its peak, has United come close to breaking even again.

Although the carrier won huge concessions from its labor unions and boasts an industry-leading on-time record, its business strategy so far reflects little new thinking.

Early this year, United's latest chief executive officer, former oil executive Glenn Tilton, insisted the carrier had little choice but to mimic Southwest Airlines' no-frills service. Then, after winning bigger-than-expected pay cuts in his mainline operation, Tilton scaled back the plan for his own discounter by two-thirds.

Instead, United is returning to its strategy of attracting elite business travelers, even though executives are flying less and paying lower fares.

Despite a long history of workplace turmoil, Tilton also is counting on harmony in labor relations. The long-term contracts herald a new era of peace with workers, he said. "I have the sense they believe this is a point of departure for United, a genuine new beginning."

With a helping hand from the federal government, the airline expects to emerge from bankruptcy in coming months. But after hacking the pay, work rules and governance rights of his unions, Tilton risks a backlash.

United remains saddled with an enduring legacy of distrust that could hold it back in a volatile marketplace.

"We've got to find a way to not peak in the good years and to go into these tremendously low valleys in the bad years," said Paul Whiteford, the pilots' union leader who sits on United's board. "Because ... if that cycle continues, the next time we may not come out of it."

During economic storms, United always faces a challenge in getting employees to accept sacrifices that make the airline more competitive. Even after the Sept. 11 tragedy and the deep falloff in air travel, employees initially balked at signing on to long-term changes.

In daily morning meetings, at United's Elk Grove Township, Ill., headquarters in the weeks after the attacks, Goodwin, Studdert, President Rono Dutta and a dozen or so of their top lieutenants struggled to perform triage.

Sensing the trouble ahead, United would lay off 20,000 workers and lose a mammoth $1.16 billion in the quarter that included Sept. 11 _ the worst three-month showing in the company's 75-year history and almost triple American Airlines' loss.

Goodwin and his team needed to convince employees that the airline couldn't sustain …