U.S. airlines are continuing to cancel flights in unusually high numbers on Monday.
According to FlightAware, 1,020 flights within, into or out of the U.S. had been canceled by early Monday afternoon at 1 p.m. Eastern time as the omicron Covid-19 pandemic fuels high call-out rates.
Among the mainline U.S. carriers, Alaska Airlines continues to have the highest cancellation rate, with 20% of scheduled flights for Monday having been called off, according to FlightAware.
In addition, Horizon Air (Alaska's regional subsidiary) had cancelled 11% of its Monday schedule.
Alaska Airlines, which maintains its largest base in Seattle, had a day of operational chaos on Sunday, canceling 28% of mainline operations. A rare winter storm dumped several inches of snow across the Pacific Northwest city.
The airline says all their cancellations at this point are weather-related. Alaska had 29 Covid-related cancellations on Dec. 23 through Dec. 26. Today, they have cancelled more than 120 flights as they reset from the weekend's storm. They expect more cancellations throughout the day.
Other U.S. airlines said staff call-outs due to omicron are continuing to force them to pare down flying.
United said it canceled 115 of its more than 4,000 scheduled mainline and regional flights on Monday due to omicron staffing issues.
American, which largely avoided omicron related issues over the Christmas weekend, also said Covid-related sick calls led it to proactively cancel flights that had been scheduled for Monday. The carrier had cancelled 84 mainline network flights by early afternoon, according to FlightAware, amounting to 3% of its mainline schedule.
Delta, meanwhile, blamed omicron call-outs as well as winter weather in its hub cities of Seattle, Minneapolis and Salt Lake City for more than 200 mainline and Delta Connection regional cancellations Monday.
Other U.S. airlines have also continued to cancel flights at high rates. Notably, Allegiant had canceled 8% of its Monday schedule as of early afternoon, while Spirit had canceled 7% and JetBlue had canceled 6%.
SkyWest, the largest U.S. regional airline, had canceled more than 250 flights, or 11% of its Monday schedule. SkyWest operates flights under the Alaska, American Eagle, Delta Connection and United Express brands.
Faring better were Frontier, which had canceled just four flights for the day, and Southwest, which had canceled 1% of its schedule, though none due to omicron staffing issues, the carrier said.
Monday's cancellations followed a challenging weekend for U.S. carriers. Omicron call-outs and weather challenges in the Pacific Northwest were the primary reasons that U.S. airlines cancelled 1,400 flights on Sunday, which amounted 6.6% of their combined schedules. In addition, 30% of U.S. airline-operated flights arrived late Sunday, according to FlightAware.
U.S. carriers canceled 5% of their flights on Christmas Day and 3.4% on Christmas Eve. By comparison, they canceled no more than 1.1% of flights in the four days that preceded Dec. 24.
Overall, Delta canceled the most mainline flights over the three-day weekend at 672, followed by United with 603.