NEW YORK, Dec 24 (Reuters) - U.S. airlines canceled hundreds of flights on Christmas Eve amid a surge in COVID-19 infections driven by the Omicron variant but millions of wary Americans carried on with travel plans through a second pandemic-clouded winter holiday. United Airlines and Delta Air Lines (DAL.N) both canceled dozens of Christmas Eve flights because of staff shortages amid the surge in infections. United Airlines canceled 177 flights and Delta canceled 150 flights, data from the website FlightAware showed as of 11:56 a.m. Eastern Time (1656 GMT). More than 2,100 flights globally were scrapped, with 527 cancellations within, into, or out of the United States, according to the site. The cancellations upended some plans but many Americans pushed ahead with holiday travel. Moses Jimenez, an accountant from Long Beach, Mississippi, flew to New York with his wife and three children, even though the latest torrent of coronavirus cases dashed their hopes to catch a performance of "Hamilton" or visit some museums. "Hamilton" was one of a dozen Broadway shows forced to cancel shows this week when cast and crew members tested positive for COVID-19. Museums were scratched from the family"s itinerary because many now require proof of vaccination and the two younger children are ineligible for the shot. Instead, Jimenez, 33, said his brood would make the most of roaming city streets and parks and seeing relatives and friends. On Christmas Day, they plan to enjoy a home-cooked meal, a family tradition, at their Airbnb lodging. "We just wanted to get out of the house, really, get the kids out to the city for Christmas," Jimenez told Reuters on Thursday at New York"s LaGuardia airport. COVID-19 infections have surged in the United States due to the fast-spreading Omicron variant, which was first detected in November and now accounts for nearly three-quarters of U.S. cases and as many as 90% in such areas as the Eastern seaboard. The average number of new COVID-19 infections has risen 37% to 165,000 per day over the past week, according to a Reuters tally. As Omicron spreads, the Biden administration announced it would lift travel restrictions on eight southern African countries imposed last month after the variant was detected there. White House spokesman Kevin Munoz tweeted that the restrictions had bought America time "to understand Omicron" and "know our existing vaccines work." read more SURGING INFECTIONS AND TRAVEL Daily totals of deaths and hospitalizations, considered lagging indicators, were little changed nationwide over the past seven days, but have jumped 55% and 28%, respectively over the course of December. Friday"s flight cancellations were prompted by a spike in Omicron cases which "had a direct impact on our flight crews and the people who run our operation," United said in a statement. The Transportation Security Administration on Thursday screened 2,187,792 passengers through U.S. airports, a decrease of about 364,000 over the number of travelers it screened pre-pandemic on the same date in 2019. While Americans scrambled for COVID-19 tests and weighed varying public health guidance - U.S. officials have said that people who are fully vaccinated should feel comfortable proceeding with holiday travel - many were determined to enjoy some semblance of celebrations and tradition. In-person Christmas services were planned at all churches and parishes in the Roman Catholic Archdiocese of New York, which includes more than 2.5 million worshipers across 10 counties and mask-wearing and social distancing measures will remain in effect, said spokesperson Joseph Zwilling. Omicron"s rapid spread will also put a damper on New York"s iconic New Year"s Eve celebration for a second straight year. Mayor Bill de Blasio said attendance for the midnight ball drop in Times Square will be capped at 15,000, roughly a quarter of the typical pre-pandemic crowd size. Many New York holiday visitors planned to limit themselves to much smaller gatherings. Madeleine Kennedy, a ski instructor from Lake Geneva, Wisconsin, flew to New York on Thursday armed with a trove of COVID testing kits ahead of a scaled-down Christmas affair with family in the borough of Queens. “The second time around, I think the world is less shocked and I think we"re going to be able to plow through this,” Kennedy said.