CHICAGO, Feb 27 (Reuters) - Delta Air Lines DAL.N said on Friday it will buy 34 more Airbus AIR.PA A321neo jets as part of its plan to refresh its fleet with aircraft that burn less fuel and offer more premium seats.

The new planes are due to arrive starting in 2029.

The order lifts Delta's total commitment for the A321neo to 189 aircraft. The airline already flies 92 of them and has 97 more on firm order. It holds options for another 36.

The deal marks the Atlanta-based airline's third aircraft announcement this year. In January, it ordered 30 Boeing BA.N 787‑10 jets, and later added an order for 31 Airbus widebody aircraft.

Delta, like other major carriers, has been adding newer jets that are more efficient and have more seats in premium cabins.

The airline has said most of its planned seat capacity growth will come from those higher‑priced seats rather than the main cabin.

The A321neo is expected to be a key part of that strategy on domestic and shorter international routes.

Delta said the aircraft has the lowest operating cost per seat among its narrowbody jets and carries more first-class and extra-legroom seats than any other single-aisle aircraft in its fleet.

The new aircraft will be powered by RTX's RTX.N Pratt & Whitney GTF engines.

(Reporting by Rajesh Kumar SinghEditing by Rod Nickel)

((rajeshkumar.singh@thomsonreuters.com; +1-313-484-5370; Reuters Messaging: rajeshkumar.singh.thomsonreuters.com@reuters.net/))