Southwest Airlines cancels two-thirds of its flights Monday

After days of paralyzing winter weather over Christmas weekend, thousands of Southwest Airlines flights have been canceled — stranding holiday travelers across the country.

Over 3,600 flights in and out of the US were canceled on Monday, with an additional 6,120 flights delayed, according to flight tracking website FlightAware.

Southwest Airlines alone canceled over two thirds of its scheduled flights — roughly 2,700 — as of 5 p.m. Monday. No other American airline company canceled as significant a number of their flights.

Southwest canceled around 300 flights in the span of just a half hour at one point Monday afternoon.

“With consecutive days of extreme winter weather across our network behind us, continuing challenges are impacting our Customers and Employees in a significant way that is unacceptable,” Southwest said in a statement on Monday.

“And our heartfelt apologies for this are just beginning.”

The airline, which is the largest carrier in 23 of the top 25 travel markets in the US, said it was working to alleviate the “wide-scale disruption” by moving around planes and crew members where they are most needed.

CNN reported that the airports that have been most affected by the cancellations are Denver, Las Vegas, Chicago Midway, Baltimore/Washington, and Dallas Love Field — where Southwest is based.

Southwest said it anticipates additional changes ahead of the New Year travel period. The airline told CNN that “those whose flights have been canceled may request a full refund or receive a flight credit, which does not expire.”

 Scott Keyes, the founder of Scott’s Cheap Flights, told the news outlet it could take up to a week before flights return to normal.

“When there’s more than 10,000 flight cancellations over the past week, it takes time for airlines to work through and reaccommodate the backlog of travelers,” he said in an email.

“While it will depend on the weather forecast (which looks promising for much of the country) and what number of travelers wind up canceling their holiday plans, I’d expect that by next week, things will have largely returned to normal,” Keyes said.

On social media, customers griped about long lines to speak with representatives as well as problems with lost baggage and excessive wait times or busy signals on the airline’s customer service lines.

Many travelers are not even able to reach a customer service agent to make changes. Southwest told CNN it is “fully staffed to answer calls,” but the outlet was not able to get through to speak to an agent.

Keyes said travelers are having trouble rebooking their flights because there were already so few seats available in the popular holiday travel season between Christmas and New Year’s Day.

Meanwhile in Buffalo, which was walloped by snow and bitter cold this weekend, the airport said it expects to reopen on Tuesday.