Southwest Airlines

(LUV) - Get Report

said demand for tickets outstripped increasing supply in November, allowing the carrier to fill more seats on its planes than a year ago.

The low-cost carrier said traffic, a measure of demand expressed in revenue passenger miles, increased 14.1% to 4.3 million last month from 3.8 million in November 2003. Southwest's capacity, as measured in available seat miles, also grew, but not by as much. Available seat miles increased 11.1% to 6.6 million from 5.9 million year over year.

Southwest was able to fill 65.5% of its seats during the month, up 1.8 percentage points from a year before.

Although demand at many carriers is rising, it's not necessarily leading to higher revenue for U.S. airlines. Industry overcapacity and fierce price competition have made it difficult for airlines to raise ticket prices.

On Thursday,

Continental Airlines

(CAL) - Get Report

said unit revenue was flat to slightly higher in November, an indication the hypercompetitive environment continues. The industry pays close attention to Continental's revenue figures because it's the only major U.S. figure to release unit revenue along with its traffic results.

Southwest shares finished Thursday's session down 2 cents, or 0.1%, at $16.30.