The order, which was first reported on Wednesday, includes 25 Airbus A350-900 aircraft and 25 advanced Airbus A330-900neo aircraft, Delta said. It follows a closely fought competition with Boeing, which had offered its 787 Dreamliner.

Airbus emerged as the front-runner in part after it became clear its revamped A330neo could be delivered earlier than Boeing's temporarily sold-out 787 Dreamliner, according to one person familiar with the discussions.

Delta plans to take delivery of the A350s beginning in the second quarter of 2017 and the A330neos in 2019. They replace Boeing 747-400 and 767-300ER planes, respectively, with 20 percent reduction in cost savings per seat, Delta said.

(Reporting by Sai Sachin R in Bangalore and Alwyn Scott in Seattle; Editing by Sriraj Kalluvila and Grant McCool)

Stocks treated in this article : AIRBUS GROUP, The Boeing Company, Delta Air Lines, Inc.