Chicago ? United Airlines finally left bankruptcy Wednesday, a leaner and more cost-efficient carrier after a painful restructuring that began in 2002 and lasted a record 1,150 days.

The nation’s No. 2 airline announced it had filed its exit documents Wednesday in U.S. Bankruptcy Court, officially ending the longest and costliest bankruptcy of any airline.

United marked the event in low-key fashion, sending top executives to airports around the country to thank United employees and customers for their patience.

“We have achieved a great deal in our restructuring to reposition this company and build upon our assets, an unrivaled global network and our dedicated employees,” said Glenn Tilton, CEO of United and parent UAL Corp.

But, in an apparent nod to the fact United still hasn’t posted a profit since 2000, he added: “We can be better.”

Passengers likely did not notice an immediate difference, since United never stopped flying even when multibillion-dollar losses forced it to seek protection from its creditors in federal bankruptcy court. But the Elk Grove Village, Ill.-based airline has made one change after another since early in its three-year overhaul.

Ludy Gerardi, left, a United Airlines ticketing agent, greets Pete McDonald, United's chief operating officer. McDonald thanked employees for their services Wednesday in the United terminal at Chicago's O'Hare International Airport.

It now has about 30 percent fewer employees (58,000), 20 percent fewer airplanes (460) and 20 percent lower operating costs (7.5 cents per seat per mile), excluding fuel, than it did when the bankruptcy began Dec. 9, 2002. Labor costs are down by more than $3 billion annually after two steep pay cuts and the elimination of defined-benefit pensions. Dozens of daily domestic flights have been eliminated.

Some things are up, too, including the number of international routes, on-time arrivals, the percentage of seats filled and the cost of on-board meals, no longer free to all.

United has added or expanded products. It has its 2-year-old discount airline Ted for leisure travelers, an enlarged Economy Plus program with more leg room for those willing to pay for it, and a premium service called “p.s.” between New York and California that offers DVD players and specialty drinks.