RICH THOMASELLI | TravelPulse.Com

Troy Warren for CNT #Travel

What the airlines were able to avoid over the Thanksgiving holiday is coming back to bite them – hard – with Christmas a day away.

More than 4,000 flights scheduled for today, Christmas Eve, as well as for Christmas Day on Saturday have been delayed or canceled worldwide, according to The Hill, which cited data from flight tracking website FlightAware.

So far, United Airlines, Delta and American have all been affected. In fact, The Hill noted that of the 4,604 flights delayed or canceled as of this morning, some 20 percent involved trips into or out of the U.S.

“The nationwide spike in Omicron cases this week has had a direct impact on our flight crews and the people who run our operation,” United said in a statement. “As a result, we’ve unfortunately had to cancel some flights and are notifying impacted customers in advance of them coming to the airport. We’re sorry for the disruption and are working hard to rebook as many people as possible and get them on their way for the holidays.”

Delta told The Hill Delta it has “exhausted all options and resources – including rerouting and substitutions of aircraft and crews to cover scheduled flying – before canceling around 90 flights for Friday.”

Airlines were able to weather the 10-day Thanksgiving holiday period with flying colors, with few delays or cancellations amidst a post-pandemic record number of travelers.

Part of that was an airline initiative to incentivize employees to work extra days, for extra pay or other perks, during the holidays between Thanksgiving and New Year’s.

But the surging Omicron variant has apparently caused havoc in staffing, though apparently it has not dimmed the enthusiasm among the flying public to take to the air. According to the Transportation Security Administration (TSA), more than 2 million travelers per day have been screened at U.S. airports in seven of the last eight days between Thursday, December 16 and Thursday, December 23.

The one day that didn’t hit 2 million, Tuesday, December 21, the final tally was 1,979,089. That was 99 percent of the capacity that flew on the same day in 2019, which the industry uses as the barometer to chart its comeback from the pandemic.

In fact, the next day, Wednesday, December 22, 2,081,297 passengers went through security – the first time in 21 months that the number of fliers beat a 2019 number, as 1,937,285 were screened on that date two years ago.