The carrier said $309 million of the charges relate to an agreement with the Pension Benefit Guaranty Corp that modifies its duty to issue up to $500 million of senior notes.

There were also costs of about $99 million tied to integrating systems and training, repainting planes and severance associated with job cuts.

The company also cited $21 million in costs from its joint collective bargaining agreement with the Air Line Pilots Association union that was ratified in December, as well as a charge of $24 million tied to the estimated fair value of foreign takeoff and landing slots.

The carrier said it expected an income tax benefit of $9 million and a gain on sales of assets of $14 million.

United, which has been looking to win back customers who turned to rivals after technology changes hurt service last year, said it will report quarterly earnings on January 24.

Analysts on average expect a loss of 54 cents, compared with a year-earlier profit of 30 cents, according to Thomson Reuters I/B/E/S.

(Reporting by Karen Jacobs; Editing by Leslie Gevirtz)