Travelers at airports across the United States were left delayed and frustrated as airlines canceled and delayed thousands of flights on Monday.
On Monday evening, 3,917 flights within, into or out of the United States had been canceled, according to FlightAware, and an additional 7,798 had been delayed.
U.S. airlines canceled more than 12,000 flights from Wednesday through Saturday, which accounts for 14% of their schedules, CNBC reported.
According to the data from FlightAware, Southwest Airlines had more cancellations and delays than any other airline, accounting for 44%. Denver International Airport accounted for the majority of cancellations, though airports from coast to coast saw dozens of cancelations.
The cancellations and delays are the result of extreme weather that stretched from the Canadian border to the Mexican border and impacted approximately 60% of the U.S. population, according to The Associated Press.
In a staff note on Saturday, Southwest’s COO, Andrew Watterson, cited a list of challenges, which included unexpected fog in San Diego, staffing shortages in Denver and equipment facing frigid temperatures in other cities, according to CNBC.