Delta Air Lines said Thursday that it will stop flying Boeing 777s by the end of the year, a 25% reduction to the widebody portion of its fleet used chiefly for international flights.

Separately, the airline signaled it might have to reduce the size of its 14,000-person pilot corps. In a memo seen and reported by Reuters, a Delta executive said that, even with scheduled retirements into next year, it will have around 3,000 more pilots than it will likely need by mid-2021.

Together, the actions show executives of Delta, the dominant carrier at Minneapolis-St. Paul International Airport, expect travel to be constrained by the coronavirus and recession into 2021 and for the airline to shrink in size, as a result.

"We're making strategic, cost-effective changes to our fleet to respond to the impact of the COVID-19 pandemic while also ensuring Delta is well-positioned for the recovery on the backside of the crisis," Gil West, the company's chief operating officer, said in a statement announcing the 777 phaseout.

Two weeks ago, Delta said it would retire its MD-88 and MD-90 aircraft in June, taking 76 planes out of service. The phaseout of the 777s involves 18 planes. Jointly, that amounts to about 10% of its 900-plane fleet.

Delta has parked about 650 planes since demand for air travel plunged in February as the virus spread around the world. More than 37,000 of Delta's employees voluntarily took an unpaid leave of absence and the airline slashed nearly all its discretionary spending.

Those moves are saving the company about $550 million a month, executives said. But, even flying a sharply reduced schedule, Delta is burning through about $50 million in cash daily.

Now, as some economic activity begins to resume in the U.S. and other parts of the world, executives are planning a comeback as a smaller operation.

The company's chief executive, Ed Bastian, told investors last month that Delta could also retire other planes, such as its Boeing 767s and 757s, and some smaller planes in its regional jet fleet that it planned to use for only a few more years. "Many of the things that we were on a path to do, I think we shortened that pathway considerably as a result of this crisis," Bastian said.

Other airlines have also accelerated plans to retire older aircraft. Some have put new aircraft orders on hold.

Delta acquired its first Boeing 777 in 1999 and began to fly them regularly on international routes at MSP about a decade ago when it started to retire its Boeing 747s.

The Airbus A350-900s models that are the newest part of its widebody fleet burn 21% less fuel per seat than the 777s.

The airline's widebody fleet will go forward with 42 Airbus A330s and 13 A350s.

Meanwhile, the exit of the McDonnell Douglas single-aisle planes will be particularly noticeable for fliers at MSP. About nine years ago Delta made MSP a hub for the older aircraft, which featured twin, rear-mounted engines.

In more recent years, Delta purchased the new Airbus A321 and more Boeing 737s with a plan to phase out the MD-88 by the end of 2020. It was still flying 47 MD-88s when the virus slowdown began. Until last month, Delta had not announced a retirement date for the MD-90s, which it first started flying in 1989 and still had 29 in its fleet.