Thousands of flights around the world were canceled Monday as airline staffers called out sick with COVID-19, but Philadelphia travelers were largely spared from the holiday disruptions.

More than 1,100 flights were canceled into, within, or out of the United States as of 5 p.m., and nearly 5,000 were delayed, according to FlightAware.com, which provides flight tracking data. That followed thousands of global flight cancellations on Christmas Eve and Christmas Day, as more travelers boarded flights this year to spend the holiday with their families.

But things were running smoothly at Philadelphia International Airport (PHL), where six departing flights, or 1%, were canceled. Two fights arriving to PHL were also canceled, and 115 total flights were delayed as of 5 p.m., according to FlightAware.

“We are fortunate to have not been impacted like other airports across the country,” PHL spokesperson Heather Redfern said.

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Roughly two million people passed through screening checkpoints each day in the U.S. last week, according to the Transportation Security Administration. On some days, that was more than double the number of travelers compared with last year.

Some airlines cited staffing issues as the omicron variant of the coronavirus rapidly spread. That included American Airlines, the world’s largest air carrier and Philadelphia’s dominant airline, with about 70% of traffic at PHL.

In Philadelphia, American canceled two flights, or 1%, of scheduled departures. The airline canceled no flights at PHL on Sunday, according to American. Overall, American canceled 3%, or 87, of its global flights by 5 p.m. Monday, according to FlightAware.com.

“Unfortunately a number of COVID-related sick calls led us to make the difficult decision to precancel some flights scheduled for today,” American spokesperson Andrew Trull wrote in an email. “We proactively notified affected customers yesterday and are working hard to re-book them quickly. We never want to disappoint our customers and apologize for any disruptions to their holiday travel plans.”

Trull said operations were otherwise running smoothly. As of 11:15 a.m., more than 80% of flights departed PHL on time and nearly 90% arrived on time. That’s consistent with American’s performance this year. Year-to-date, American has averaged an 80% on-time departure rate and an 85% on-time arrival rate from PHL, according to the airline.

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The cancellations “were on the news this morning, but there was no problem at all,” said Christopher Mitchell, a 25-year-old stationed at Joint Base McGuire-Dix-Lakehurst in Burlington County. He flew into Philadelphia on Monday from Houston.

Spokespersons for Spirit Airlines, which canceled four flights at PHL, and PSA Airlines, which had 21 delays at PHL, did not immediately respond to requests for comment. Other airlines with canceled flights either arriving into or departing PHL on Monday included Delta and SkyWest.

Even before the recent rise in COVID cases, airlines have grappled with staffing shortages as they struggled to find enough workers to meet rebounding travel demand. In a Dec. 23 letter, the industry trade group Airlines for America urged the CDC to update its isolation guidelines to get fully vaccinated staffers who catch COVID-19 back to work faster.

“As we address the omicron variant, it is important to reassess the 10-day isolation for those who are fully vaccinated,” wrote Nicholas Calio, the group’s president and CEO. “As with health care, police, fire and public transportation workforces, the omicron surge may exacerbate personnel shortages and create significant disruptions to our workforce and operations.”

Positive test results for COVID among flight attendants have increased with the omicron variant, said Sara Nelson, international president of the Association of Flight Attendants-CWA, which represents 50,000 flight attendants at 17 airlines. She said staffing remains tight as workers are hesitant to pick up voluntary overtime due to disruptive passengers, COVID concerns, and COVID test positives during the busiest travel period of the year.

”We have negotiated holiday incentives to help with operational challenges, but there’s only so far you can stretch people,” Nelson said in a statement. ”It’s also important to recognize that some of the cancellations and delays are weather related. This is typical and it’s a good reminder that flights only take off when it’s safe to do so.”

Rose Miller, who came from Cleveland to see family in Philadelphia, didn’t run into any flight issues on Monday. The only delay was waiting for her sister at baggage claim.

“On each flight we were early,” she said. “It was great, believe it or not.”