Boeing 767-400 of United Airlines
Boeing 767-400 of United AirlinesiStock

US airlines scrapped nearly 1,000 flights on Saturday, the second straight day of massive cancellations as surging COVID-19 infections have sidelined some pilots and other crew members, Reuters reports.

A total of 957 Christmas Day flights, including domestic flights and those into or out of the country, were canceled, up from 690 on Christmas Eve, according to flight-tracking website Nearly 2,000 flights were delayed.

At least one airline said that it expects hundreds more cancellations on Sunday.

The cancellations have been caused by the rapid spread of the highly transmissible Omicron variant of COVID-19, which has led to a sharp increase in infections and forcing pilots and crew to be quarantined.

United Airlines canceled 230 flights while American Airlines called off 90 flights, representatives for the companies said in separate statements.

Winter weather and Omicron forced Delta Air Lines to scrub 344 flights on Saturday, of approximately 3,000 scheduled flights.

The CDC said earlier this week that Omicron is now the dominant version of the coronavirus in the US, accounting for 73% of new infections last week.

On Monday, the US recorded its first death from the Omicron variant, an unvaccinated Houston man in his 50s with underlying health conditions.