Chicago ? The parent company of United Airlines reported a worst-ever quarterly loss of $1.5 billion Friday, capping off a year of record losses that pushed it into Chapter 11 bankruptcy in December.

UAL Corp.’s dismal results brought to $3 billion the total fourth-quarter losses for all the major U.S. airlines, aside from US Airways, which also is in bankruptcy and did not issue a report.

For the year, the nation’s major airlines reported a combined loss of more than $9 billion.

The industry has been in crisis since the Sept. 11, 2001, terrorist attacks compounded existing problems from an economic downturn.

CEO Glenn Tilton said United would make “difficult but critical” changes in bankruptcy. He did not disclose specifics, pledging only that United will “compete aggressively” in 2003.

But the carrier warned that it expected another sharp loss for the first quarter in view of weaker international bookings. A war in Iraq also would worsen its predicament, it said.

The fourth-quarter deficit left UAL with a net loss of $3.2 billion for the year — just shy of the industry-record $3.5 billion suffered by American Airlines’ parent, AMR Corp., in 2002.

UAL’s net loss for the last three months of the year was $1.47 billion, or $20.70 a share, compared with a fourth-quarter 2001 loss of $308 million, or $5.68 a share.

Excluding certain items, United said its quarterly loss was $9.65 per share — better than Wall Street expected. Analysts surveyed by Thomson Financial had estimated the per-share loss at $13.81. It was United’s 10th-straight quarterly loss. Since last turning a profit in the second quarter of 2000, United has lost $5.5 billion.

Airline analyst Ray Neidl said it was premature to judge United’s emerging strategy until details were released. The pilots and flight attendants unions have denounced the possible creation by United of a discount airline.

Employees may “come around to reason when they look at the alternative, which is total liquidation,” said Neidl, of New York-based Blaylock & Partners.

For the year, the net loss amounted to $53.55 per share, compared with a year-earlier loss of $40.04 a share. Revenues sank 11 percent to $14.3 billion from $16.1 billion.