U.S. airlines began canceling Sunday flights and waiving cancellation and change fees for airports from Virginia to Maine ahead of another massive winter storm on the East Coast, set to once again put carriers to the test at the tail-end of winter break.

Delta Air Lines, American Airlines, JetBlue Airways, United Airlines and Spirit Airlines waived fees and fare differences for passengers if they can travel as late as Feb. 26. Southwest Airlines said customers are eligible for a change without paying a difference in fare if they can rebook to fly or fly standby within two weeks.

The storm could bring between 13 and 18 inches of snow to parts of southern Connecticut and southeast New York, as well as winds of up to 55 miles per hour, according to the National Weather Service. The blizzard warning is set to begin at 6 a.m. ET Sunday.

As of 4:30 pm ET Saturday, close to 400 U.S. flights were canceled, according to FlightAware. Delta had the most, with 174 cancellations or 5% of its mainline schedule. New York airports, which make up a major Delta hub, were the most affected by Sunday’s disruptions.

The National Weather Service raised its initial assessment of the potential severity of a storm. The weather service now says 1 to 2 feet (about 30 to 61 centimeters) of snow is possible in many areas. Blizzard warnings were also issued for New York City, Long Island, southern Connecticut and coastal communities in New Jersey, Delaware, Rhode Island and Massachusetts.

The weather service warned that the storm’s steady winds of 25 to 35 mph (40 to 56 kph) would “make travel dangerous, if not impossible.”

Winter Storm Fern in January, followed by bitter cold, caused mass travel disruptions across a large swath of the U.S.

American Airlines had struggled to recover, drawing harsh criticism from flight crews, some of whom were stranded and had to sleep at airports, heightening tension between frontline employees and the company’s CEO, Robert Isom.

The storm cost American between $150 million and $200 million in revenue, the carrier said last month on an earnings call.

— The Associated Press contributed to this report.

American Airlines flight attendants’ union held a picket outside the company’s headquarters on Thursday pushing for new leadership at the carrier, which has lagged rivals Delta Air Lines and United Airlines in profitability and punctuality.

Ahead of the picket on Wednesday night, American CEO Robert Isom sought to calm frustrated employees and listed improvements the carrier expects this year, including a jump in profits as well as improvements to schedules and new cabins.

“We look forward to working with all of you to make it happen,” Isom said in a video message filmed at the airline’s Fort Worth, Texas headquarters.

The picket came days after the Association of Professional Flight Attendants, representing American’s 28,000 cabin crew members, issued a vote of no confidence in Isom, which the union said was its first such move. The chief executive was also criticized by the pilots’ union, which sought a meeting with the airline’s board, of which Isom is a member, to discuss the problems. Unions for pilots, flight attendants and mechanics have all recently said the company needs to do better to improve reliability and financial results.

The protest is an unusual move outside of contract negotiations.

The signals from the labor groups have increased pressure on Isom, who took the helm nearly four years ago, and American’s leadership team, which is investing in cabin upgrades, bigger airport lounges and other on-board products.

Last month, American forecast stronger revenue and profits for 2026 and said it expects to report adjusted earnings per share of as much as $2.70, up from an adjusted 36 cents last year.

American is in the middle of a revamp that it hopes will help revive profits with more modern airplane cabins that command higher fares, which is especially important as coach-class fares have dropped. It has also built bigger lounges and added free Wi-Fi for customers.

For the first 11 months of the year, American ranked eighth in punctuality with a 73.7% on-time rate, according to the Department of Transportation. It is now adjusting its schedules, including at its massive Dallas-Fort Worth International hub where it is spreading out flights more throughout the day.

But it has a long way to go. In 2025, American posted net income of $111 million compared with Delta’s $5 billion and more than $3.3 billion from United. The lower profits meant a smaller profit-sharing pool for employees, which staff members have complained about.

In a town hall with employees last month, Isom noted that American’s pilots, flight attendants and other groups have recently sealed new labor contracts that have meant higher wages compared with their counterparts at rival United. But he said he was disappointed by the profit-sharing.

The flight attendants have also said they were frustrated with American’s struggles to recover from major winter storms, which left some crew members without a place to sleep.

Picketing crew members on Thursday carried signs that said “everything froze, AA melted down,” referring to the disruptions, and “Failed Ops=Failed CEO,” nodding to the carrier’s operation.

“This airline is headed down a path that puts our careers at risk,” the flight attendants’ union said in a notice about the picket. “Now is the time for Flight Attendants to stand together and show up in protest. American Airlines needs real accountability, decisive action, and leadership that will put this airline back on a competitive path.”

Isom is also trying not only to win support of frontline crews but also to rally higher-ups. Last week, at Globe Life Field in Arlington, Texas, Isom spoke to about 6,000 managers about the years ahead as the airline turns 100.

“We’ve filled an entire Major League Baseball field with this proud and talented team. The best in the industry,” he said, according to a transcript of his remarks, which were seen by CNBC. “It’s incumbent on all of us to build on our progress … and to ensure that we grow profitability so American is around for the next 100 years.”