(Reuters) - American Airlines said on Tuesday it took delivery of the first of 14 Boeing extended range 777-300 planes it has ordered.

The twin-aisle plane, which has more than 300 seats and offers first class, business class and main cabins, will be used on the Dallas/Fort Worth to Sao Paulo route in early 2013.

American, a unit of AMR Corp , said the plane would also fly to London Heathrow Airport from Dallas/Fort Worth and New York's John F. Kennedy Airport.

American, which is currently operating under Chapter 11 bankruptcy protection and weighing a potential merger with US Airways Group , said it was the first U.S. airline to order and take delivery of the 777-300ER.

The carrier is modernizing its fleet and has more than 550 planes on order.

(Reporting by Karen Jacobs; Editing by Tim Dobbyn)