According to the flight tracking website FlightAware.com, 957 domestic and international flights were canceled on Christmas Day, up from 690 on Christmas Eve. About 2,000 other flights were delayed.
And at least one airline said it expected more cancellations Sunday. A United Airlines spokesperson said the company had canceled 230 flights.
The site data showed that Delta Air Lines canceled 292 flights as of 16:23 GMT, while an American Airlines spokesman said it had to cancel 90 domestic flights.
Globally, more than 2,500 flights were canceled in total, on Saturday, and about 4,200 other flights were delayed.
The Christmas holidays are usually prime time for air travel, but the rapid spread of the Omicron strain has led to a sharp increase in COVID-19 infections, forcing airlines to cancel flights as pilots and flight crews must be quarantined.
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