Flying against the headwinds of a recession and volatile fuel prices, Southwest Airlines Co. made money in the fourth quarter and extended its string of annual profits to 37 years.

Southwest said Thursday it earned $116 million in the quarter, which was enough to lift the company to a full-year profit of $99 million after it lost money during the first nine months of 2009.

Traffic on the nation's largest discount carrier has been rising in recent months while it's been falling on many competitors.

Chairman and CEO Gary C. Kelly said a "dramatic" drop in business travel during the recession made this "perhaps, the most difficult revenue environment the airline industry has ever faced."