With the exception of Southwest, several of the nation's largest airlines reported significant declines in passenger demand during December compared with the previous year.

American, America West and Continental each reported double-digit percentage declines for the month, although their data provide evidence that business is gradually rebounding from Sept. 11.

The stocks of most major airlines rose Friday on the news.

Southwest said traffic grew by 0.6 percent to 3.55 billion revenue passenger miles, a measure of the number of paying customers who travel one mile.

American, the nation's largest airline, said traffic fell 17.4 percent to 9.08 billion revenue passenger miles. America West said reported a 15 percent drop to 1.34 billion revenue passenger miles. Continental said traffic slipped 10 percent to 4.5 billion revenue passenger miles.

In November, industrywide passenger demand was down 20 percent from the previous year, according to the Air Transport Association.