• Boston and New York City-area airports were the most affected by the weather.
• Airlines waived fare differences for travelers to change trips flights ahead of the storm.
• Most carriers got rid of change fees in 2020 for standard economy tickets.

Airlines have canceled thousands of flights as a winter storm bears down on the Northeast, bringing high winds and the potential for more than a foot of snow in some areas.

Winter storm warnings were in effect Friday through much of Saturday from Maryland to Maine, according to the National Weather Service.

Carriers canceled more than 3,500 U.S. flights scheduled for Saturday after more than 1,400 on Friday, according to flight-tracker FlightAware.

Travel disruptions will last into part of Sunday. Delta Air Lines said Friday that it planned to suspend operations at New York's LaGuardia Airport, John F. Kennedy International Airport, Newark Liberty International Airport and Boston Logan International Airport from Saturday through Sunday morning "as airfields and ground transportation infrastructure are expected to be impacted."

Delta cut 461 mainline flights or 19% of its Saturday schedule, according to FlightAware.

New York-based JetBlue Airways, which also has a major operation out of Boston, cut half of its Saturday schedule, or 418 flights.

At Boston Logan, 616 Saturday flights were canceled, more than 90% of the schedule. Almost all service more than 560 flights, was canceled at LaGuardia and 879 at Kennedy, more than 70% of those scheduled. More than three-quarters Saturday's schedule to and from Newark, more than 80% were canceled, or 608 flights.

Regional carrier Republic Airways, which flies for American, United and Delta, canceled 427 flights, 62% of Saturday's schedule. American canceled 464 mainline flights Saturday, or 18%, while United scrubbed 396, more than a fifth of what it planned to fly.

Airlines in recent years have canceled flights sometimes days ahead of big storms to avoid customers and crews being stranded.

Carriers said they would waive fare differences for customers affected by the storm. Most airlines had already removed change fees for standard economy tickets in 2020 when the coronavirus pandemic repeatedly derailed travelers' plans.

Airlines cut more than 20,000 U.S. flights between Christmas Eve and the first week of the year, when far more people were traveling, due to a combination of bad weather and a surge in Covid infections among crews.