MIAMI — Delta Air Lines will purchase 15 more Airbus A321ceo jets. The aircraft will be used to replace Boeing 757s as they are retired from the fleet.

“This opportunistic aircraft order continues Delta’s disciplined, capital efficient approach to fleet renewal,” said Delta CEO Richard Anderson. “These new airplanes will improve the flying experience for our customers and benefit our shareholders.”

Delta’s first A321 will enter into service in early 2016. The aircraft feature CFM56 engines produced by CFM International, a joint venture of General Electric Co. and Snecma (Safran) of France just like all of Delta’s narrow-body Airbus aircraft.

There will be 20 first class, 23 Economy Comfort, and 149 economy seats on board. Each airplane will feature in-flight Wi-Fi, live satellite TV with on-demand options, and 110v power at every seat.

Delta now has 45 A321s on order total. The company ordered thirty of the jets, long with ten A330s, in the fall of 2013. The initial order came as a bit of a surprise as the carrier already had 100 of the A321s main competitor – the Boeing 737-900ER – on order.

Vinay Bhaskara, Airchive’s Senior Business Analyst, isn’t too surprised, however. “The A321 beats the 737-900ER on a CASM (cost per available seat mile) basis excluding finance costs, and it’s quite good for trunk routes in the US (case in point, both JetBlue and American have also ordered the A321 specifically for trunk routes in the past year).”

“The A321’s economic efficiency and product offering relative to the aircraft they will replace ensures that this opportunistic transaction will enhance profitability, customer satisfaction, and shareholder value for Delta,” said Nathaniel Pieper, Delta’s Vice President – Fleet Strategy and Transactions.

“Airbus is excited to offer Delta comfortable and efficient aircraft that fit its demanding financial and customer satisfaction goals,” said John Leahy, Airbus Chief Operating Officer Customers. “It is clear that the quality, comfort and economy of the aircraft were the right fit.”

Delta is targeting to reinvest approximately 50 percent of its operating cash flow back into the business which results in $2 to $3 billion of capital expenditures annually through 2018, with $2.3 billion planned for 2014.