UAL Corp , parent of United Airlines, posted a smaller-than-expected quarterly loss on Tuesday, and its shares rose 4 percent.

The carrier said its third-quarter loss narrowed to $57 million, or 39 cents per share, from $792 million, or $6.22 per share, a year earlier.

Excluding net mark-to-market hedge gains and certain accounting charges, UAL lost 43 cents per share. On that basis, analysts had expected a loss of 94 cents, according to Thomson Reuters I/B/E/S.

UAL said operating revenue fell 20.3 percent to $4.43 billion.

The airline industry has been hammered in recent years by volatile fuel costs and sagging travel demand as business cope with economic weakness.

UAL said it expected mainline unit costs, excluding fuel, profit sharing and certain accounting charges, to be down 0.5 percent for 2009.

Shares of UAL rose to $7.55 in trading before the market opened from Monday's close of $7.26.

(Reporting by Kyle Peterson; Editing by Lisa Von Ahn)