Thousands of potential travelers received last-minute cancellations of their Christmas flights on Friday and Saturday due to the recent rise in the number of Omicron cases, including airline employees.

Flight Aware showed that the number of cancellations globally on Christmas Eve and Christmas Day rose to more than 3,800, with more than 1,000 in the United States.

Although cancellations represent a relatively small percentage of the 80,000 arrivals on any given day, they have disrupted a Christmas season that has been overshadowed by the highly contagious variant Omicron that currently accounts for more than 70 percent of new coronavirus cases in the United States.

On Friday, United Airlines canceled 176 of its 4,000 domestic and international flights at dozens of airports, largely because crew members fell ill, said Joshua Fried, a spokesman for the Chicago-based airline.

At least 44 flights were canceled on Saturday.

The cancellations were caused by “a combination of problems, including temperature and associated OMicron, and Delta Air Lines expects at least 150 additional cancellations over the weekend, according to spokeswoman Kate Modulu.

Although most travelers managed to get where they were going, the hundreds of people who waited for the first Christmas season would be very close to normal when they booked their flights, and had to look for alternatives.