Omicron grounds hundreds more U.S. flights over holiday

Hundreds of flights were canceled across the U.S. for a third day over the Christmas holiday as surging COVID-19 infections grounded flight crews.

Commercial airlines canceled more than 700 flights in the U.S. on Sunday, nearly 1,000 on Christmas Day and about 700 on Christmas Eve, according to a tally on flight-tracking website FlightAware.com. Further cancellations were likely, and more than 1400 flights were delayed.

The rapid spread of the Omicron variant has led to a sharp increase in COVID-19 infections, during a peak travel time, forcing airlines to cancel flights with pilots and crew needing to be quarantined.

Delta Air Lines expected more than 300 of its flights to be canceled on Sunday, due to the virus and winter weather.

FlightAware data showed more than 2,000 flights were called off around the world on Sunday, and at least another seven thousand were delayed.

Omicron now accounts for nearly three-quarters of U.S. COVID-19 cases and as many as 90% in some areas, like the northeast. New U.S. coronavirus cases have risen 45% over the past week, according to a Reuters tally.

While recent research suggests Omicron produces milder illness and a lower rate of hospitalizations than previous variants of COVID-19, health officials remain cautious.