Airlines add seats after snowstorm hits travel

American Airlines jets taxi to and from gates at O'Hare International airport in Chicago, Illinois December 24, 2008.

ATLANTA (Reuters) - Major air carriers added extra flights on Monday to accommodate passengers whose travel plans were disrupted by a massive weekend storm that dumped as much as two feet of snow on the U.S. Northeast.

The storm buried cities from Washington, D.C., to Boston, resulted in closures or significant delays at airports and forced hundreds of flight cancellations just days before Christmas.

"All airports are open and our flights are running normally today," said Susan Elliott, a spokeswoman for Atlanta-based Delta Air Lines Inc, the world's largest air carrier.

She said Delta has added about 6,500 additional seats to flight schedules on Monday, including 22 additional flights, in heavily impacted markets. On some routes, aircraft have been upgraded to planes that have more seats to be able to serve more travelers, she said.

UAL Corp's United Airlines halted about 1,000 flights over the past weekend, or about a tenth of its global network, spokesman Rahsaan Johnson said. He said the airline is also planning to add extra flights this week.

AMR Corp's American Airlines added at least 15 extra flights to areas such as New York, Boston and Washington, spokesman Tim Smith said in an email.

American Airlines canceled about 325 flights December 18-20, and a similar number were canceled on the carrier's American Eagle regional affiliate, he said.

"We have made good progress in reaccommodating passengers and we'll continue that process today to get our customers to their destinations in time for Christmas," Smith added.

The Arca airline index was up modestly on Monday as airline stocks were mixed. Delta was down 8 cents to $11.58 in afternoon trading, while AMR was up 4 cents to $7.65. UAL was up 12 cents to $11.54, and Continental Airlines Inc gained 40 cents, or 2.3 percent, to $17.67.

(Reporting by Karen Jacobs; editing by John Wallace and Gerald E. McCormick)