ATLANTA, GEORGIADelta Air Lines is planning to operate its B757s and B767s jets beyond 2025 in the absence of new mid-market types.

"The B767 -300ER is a fleet that over the next five, seven, eight years will have to be retired. Followed by the B767-400, followed by the 757," Delta's president Glen Hauenstein said.

"What are we looking at down the road in terms of carbon fuels, environmental regulations, noise? There are so many different alternative scenarios... You don't want to get yourself in a box where you've committed specifically," he added.

The US carrier had previously stated that it would retire all of its B767-300(ER)s by the end of 2025. Delta Air Lines currently operates 48 of the mid-haul widebodies, which are 26 years of age on average. Hauenstein said that Delta would continue to operate 45 B767-300(ER)s. in 2022.

The airline also operates 21 B767-400(ER)s, which are 20.9 years old on average. The type is currently operated only by Delta, United Airlines, and Bahrain Royal Flight.

Delta's old-generation mid-market aircraft fleet also includes 111 B757-200s and sixteen B757-300s. Hauenstein said that the B757-200s will continue to serve for Delta through at least 2027, and the -300s probably even beyond that.

The airline sees airplanes such as the A321-200 and the A330-900 as an imperfect replacement for its mid-market fleet. Delta currently has 155 A321-200neos and 35 A330-900s.