(CNN) — Thousands of US flights were canceled on New Year’s Day as a combination of Covid-19 and wintry weather have slowed travel. Flight cancellations have trended up steadily since Christmas Eve, hitting a new peak Saturday morning as millions travel over the holidays.

Data from the website FlightAware shows more than 4,200 flights were canceled globally as of midday Saturday, or about 10% of the worldwide schedule.

Airlines have already been dealing with the Omicron variant, which has brought an unprecedented spike in Covid cases. Many airline employees have been unable to work. The Federal Aviation Administration has also warned more of its own employees are testing positive, which may restrict flights.

Now a new challenge is adding to travelers’ woes: a large storm is sweeping across the Rockies and Midwest, bringing ice and heavy snow. Chicago has been especially hard hit. Airlines have canceled more than half of flights from Midway International Airport and more than 40% from O’Hare International Airport. Nearly a third of flights at Kansas City International Airport have been canceled. In Detroit, airlines canceled one in five flights.

Delta Air Lines told CNN Business it projects between 200 and 300 of its more than 4,000 daily flights will be canceled during the holiday weekend. It also recommended people traveling in Chicago, Detroit, Salt Lake City, Seattle and the central and southern Rocky Mountain regions consider shifting their travel plans given the weather.

Southwest Airlines told CNN Business all of its issues have been caused by weather.

More than 11,000 flights have been canceled since Christmas Eve, according to FlightAware data.

The-CNN-Wire
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