More than 2,300 flights were cancelled around the world Friday and thousands more were delayed as the highly infectious Omicron variant disrupted holiday travel.
One route, however, was thankfully not affected: Santa was on track delivering presents to children across the globe, air defense officials assured US President Joe Biden.
According to tracking website Flightaware.com a total of 2,325 flights had been cancelled worldwide Friday as of 2015 GMT, including 616 flights originating from or headed to US airports, and more than 8,000 delayed.
Over 1,400 cancellations were announced for Saturday, Christmas Day, the site reported.
Pilots, flights attendants and other staff have been calling in sick or having to quarantine after exposure to Covid, forcing Lufthansa, Delta, United Airlines and many other carriers to cancel flights during one of the year's peak travel periods.
According to Flightaware, United cancelled more than 185 flights on Friday, or 10 percent of those that were scheduled.
"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," the airline said, adding that it was working to rebook passengers.
Similarly, Delta cancelled at least 166 flights, saying it has "exhausted all options and resources — including rerouting and substitutions of aircraft and crews to cover scheduled flying."
"We apologize to our customers for the delay in their holiday travel plans," the company said.
Eleven Alaska Airlines flights were axed, after employees said they were potentially exposed to Covid-19 and had to self-isolate in quarantine.
The cancellations added to the pandemic frustration for many Americans eager to reunite with their families over the holidays, after last year's Christmas was severely curtailed.
Huge travel bump
According to estimates from the American Automobile Association, more than 109 million Americans were scheduled to travel by plane, train or automobile between December 23 and January 2, a 34 percent increase since last year.
But most of those plans were made before the outbreak of the Omicron variant, which has become the dominant strain in the United States, overwhelming some hospitals and healthcare workers.
Luckily, Omicron did not affect Santa's travel plans, according to the North American Aerospace Defense Command (NORAD), which has tracked St. Nick's Christmas journey for over 60 years.
Major General Eric Kenny, commander of the Canadian NORAD region, told AFP that Santa had distributed over two billion gifts and was above Pakistan around 1800 GMT.
"Santa is doing very well so far," Kenny said. "He's been at it for many hours already and will go throughout the evening as well."
Biden and First Lady Jill Biden also spoke to NORAD officials via video conference Friday to make sure Santa's trip was going smoothly.
Biden then spoke, also via video call, to several American families, asking children what presents they wanted and telling them that they had to be in bed before midnight, otherwise Santa would not come.
But in a sign of deep political divisions plaguing American society, the event then took a sour turn, when a father, to whom Biden had just wished happy holidays, launched at him with an insult.
According to journalists present at the event, the father said "Merry Christmas" followed by "Let's go Brandon!" The phrase has been used by supporters of Donald Trump as a euphemism for a derogatory remark against the current president.