About 600 flights have been canceled within, into or going out of the US on Christmas Eve so far, according to flight-tracking site FlightAware.
As of 2:30 p.m. ET, exactly 602 flights were canceled and more than 1,800 were delayed.
Globally, there were nearly 2,300 flight cancellations in total, according to FlightAware.
More than 180 United Airlines flights, 165 Delta flights and 72 JetBlue fights have been canceled, according to FlightAware.
The Transportation Security Administration said it screened 2.19 million people at airports across the country on Thursday, the highest figure since the uptick in holiday travel started a week ago.