50% of all flights canceled around the world today were Southwest flights, as the airline collapsed under strain historic winter storm

Canceled flight travelers line up in front of Southwest Airlines sign at Denver International Airport. Hyoung Chang/Getty Images

• Southwest AIrlines canceled thousands of flights on the day after Christmas. 
• The Dallas-based airline accounted for almost 50% of all flight cancellations across the globe.
• The cancellations caused chaos at airports across the country, from Denver to Baltimore.

Southwest Airlines canceled nearly 3,000 flights the day after Christmas, more than any other US-based airline.

By 8:30 p.m. on December 26, Southwest had canceled 2,877 flights, or 70% of its total flights, according to FlightAware. 

Thousands of flight delays and cancellations swept the U.S. over Christmas weekend as a deadly winter storm took effect, causing heavy snowfall and power outages in the Northeast. 

By Monday night, the airports seeing the most cancellations included Denver, Las Vegas, Chicago Midway, and Dallas Love Field, where Southwest is headquartered. 

Southwest canceled the most flights of any other airline based in the US on Monday, trailed by Delta, which canceled 265 flights, according to FlightAware. United canceled 135 flights. American Airlines canceled only 12 flights, though it recorded 792 delays, accounting for nearly a quarter of all flight delays worldwide on Monday. 

One of every two flights canceled worldwide was a Southwest flight, as the airline's network collapsed under the strain of the winter storm. 

The cancellations led to chaotic scenes at airports across the country. 

A reporter for 9News in Denver tweeted Monday afternoon that some travelers at Denver International Airport, where Southwest was responsible for hundreds of flight cancellations, had been stranded for days and that the line to rebook was over three hours long. 

—Courtney Yuen (@courtyuen) December 26, 2022

Meanwhile, a reporter for ABC15 in Phoenix spoke with frustrated travelers at the Phoenix Sky Harbor International Airport as they learned that there would be no more scheduled Southwest Airlines flights for the next four days. 

—Marc Thompson (@marcthompson) December 26, 2022

In Dallas, a spokesperson for TWU Local 556, the Southwest Airlines Flight Attendants Union, blasted the airline for not investing in the needed technological improvements to avoid massive travel disruptions amid its rapid expansion in the last several years. 

—Brandon Richard (@BrandonLRichard) December 26, 2022

Southwest issued a statement Monday night apologizing for the travel disruptions, calling them "unacceptable."
The airline attributed the cancellations to the severe weather conditions, and said that customers should expect a "reduced number of flights" leading up to the New Year as it works to return to normal operations.

Southwest said it is working on contacting travelers whose flights will be impacted by the changes, and it also acknowledged that its employees had also been negatively affected by the flight cancellations.

"On the other side of this, we'll work to make things right for those we've let down, including our Employees," the statement said.

Update December 26, 2022 — Updated with a statement from Southwest Airlines and further data from FlightAware.