Delta orders 15 Airbus airliners

US carrier Delta Air Lines has ordered 15 Airbus medium-haul A321 aircraft with a total list price of $1.65 billion for delivery in 2018, the European plane maker said on Monday.

The order by Delta is for the current engine option of the aircraft, which Airbus also offers with new, more fuel-efficient engines.

Delta's new acquisition brings its total Airbus on order to 55 aircraft: 45 A321s and 10 A330s. The airline already has a large fleet, including 126 A320s and 32 A330s.

Its first A321 will begin service in early 2016, Delta said in a statement.

"These new airplanes will improve the flying experience for our customers and benefit our shareholders," said Chief Executive Richard Anderson.

The catalogue value of the contract is worth the equivalent of 1.2 billion euros, but airlines usually negotiate substantial reductions from list prices.

Delta is aiming to reinvest around half of its operating cash flow back into the business each year through to 2018, equivalent to around $2-3 billion annually.

This year the US carrier is planning to spend $2.3 billion, it said in a statement.

The aircraft will be equipped with engines manufactured by CFM, a joint venture between French manufacturer Snecma, subsidiary of Safran Group, and General Electric.