Travelers across the country are scrambling to figure out backup plans after Delta Air Lines canceled hundreds of flights amid the holidays.

First came the weather. On Wednesday, in response to a snowstorm in the Minneapolis-St. Paul area, where Delta has a major hub, the airline proactively canceled more than 250 flights scheduled for Wednesday and Thursday. Then because of staffing issues, Delta was forced to cancel approximately 100 more flights scheduled for Friday, Christmas Day.

"A number of factors have pressured our ability to timely staff several dozen scheduled flights on Friday," Delta spokesman Anthony Black said in an email.

The cancellations are a possible byproduct of the pandemic's toll on travel demand, according to Chris Riggins, a Delta pilot and communications chairman of the Delta Air Lines Master Executive Council of the Air Line Pilots Association.

"Due to the downsizing of the airline and trying to manage the size of the workforce . . . there's been some training issues that's been created from moving pilots from airplane to airplane and getting them retrained," Riggins says. "It's basically a problem of trying to get the pilots to the right place at the right time."

Delta ran into the need for cancellations over Thanksgiving as well, when the airline canceled more than 500 flights that week.

"After shrinking through voluntary leaves, buyouts and early retirements this summer and fall due to COVID-19, Delta has far fewer pilots than it did this time last year," Kyle Potter, the Minneapolis-based editor of the travel site Thrifty Traveler, said in an email. "That's fine in normal times, but when you combine the increased travel demand for Christmas with pilots taking time off for the holiday, cracks start to show."

Potter says Wednesday's snowstorm potentially exacerbated the issue because it left pilots out of place.

These issues weren't made clear to impacted travelers, who took their frustrations to Twitter. Customers lamented waiting on hold for Delta customer service for hours, their holiday plans ruined for reasons unknown to them.

When Carla Crossno and her family woke up on Christmas Eve, they discovered their afternoon flight home to Atlanta from Eagle County Regional Airport in Colorado had been canceled, although the reason was unclear.

"What we've been told is it was flight operations, that's the only information that anybody has provided to us," Crossno said.

According to Black, Delta should not need to cancel more flights because of weather. He also said Delta is working to rebook Christmas Day travelers on flights the same travel day while maintaining the airlines' blocked seat policy.

"While Delta Reservation Sales is proactively rebooking customers, they can also proactively change their travel plans without a change fee or request a refund for their canceled flight, without penalty," Black said. "As always, customers are encouraged to check flight status via Delta.com, the Fly Delta Mobile App or by email with One-Time Flight Notification."

Riggins said pilots can sympathize with frustrated holiday travelers.

"We understand how important it is to get people to their destinations and their loved ones over the holidays," he said. "We have pilots that are stepping up and doing that right now."