Delta Air Lines Inc. will pare its fleet of Boeing Co. 717 jets by at least half over the next year, continuing to cull older, more costly planes amid the collapse in demand caused by the coronavirus pandemic.

The change means Delta will stop flying the 110-passenger plane in Minneapolis and the New York City area, according to a memo sent to pilots May 15. New York service will move to Airbus SE A220s and A320s, while Minneapolis flights will be made on A320s and Boeing 737s.

The move toward newer, more fuel-efficient planes that need less maintenance highlights the ongoing shift of equipment and employees at U.S. carriers amid a drop of more than 90% in demand from a year ago and uncertainty about when passengers will return. Delta already has said it would retire its Boeing MD-88 and MD-90 aircraft and Boeing 777 planes by the end of this year. That will leave a surplus of pilots at the Atlanta-based carrier.

Parking the 717 jets will leave Delta with 30 to 45 of the narrow-body planes in service. Those in Minneapolis will be grounded by the third quarter of 2020 and the rest by the second quarter of next year, according to the memo.

Delta has been subleasing 78 of the 91 jets from Southwest Airlines Co. since 2013. There are “several years” left in the leases, said Brandy King, a spokeswoman for Dallas-based Southwest. Delta declined to say what it would do with the planes, which Boeing stopped making in 2006 and have an average age of almost 19 years.

Delta separately said it would resume some suspended routes next month, taking into account customer demand, government travel regulations and federal health guidelines. Still, its flight schedule will be “significantly reduced” from last year compared with a year ago, the carrier said in a statement. Second-quarter flying capacity will be 85% less than last year, down 80% in domestic markets and 90% internationally.