Lufthansa, United, Delta Cancel Flights Over Christmas

At least three major airlines said they have canceled dozens of flights because illnesses largely tied to the omicron variant of COVID-19 have taken a toll on flight crew numbers during the busy holiday travel season.

Germany-based Lufthansa said Friday that it was canceling a dozen long-haul transatlantic flights over the Christmas holiday period because of a “massive rise” in sick leave among pilots. The cancellations on flights to Houston, Boston and Washington come despite a “large buffer” of additional staff for the period.

The airline says it couldn't speculate on whether COVID-19 infections or quarantines were responsible because it was not informed about the sort of illness. Passengers were booked on other flights.

Lufthansa said in a statement that "we planned a very large buffer for the vacation period. But this was not sufficient due to the high rate of people calling in sick."

U.S.-based Delta Air Lines and United Airlines said they had to cancel dozens of Christmas Eve flights because of staff shortages tied to omicron. United canceled 169 flights, and Delta called off 127, according to FlightAware.

"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 to several news outlets. "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 it was working to rebook as many people as possible.

Delta said it canceled flights Friday because of the impact of omicron and possibility of bad weather after it had “exhausted all options and resources — including rerouting and substitutions of aircraft and crews to cover scheduled flying."

It said in a statement to several outlets that it was trying to get passengers to their destinations quickly.

The cancellations come as coronavirus infections fueled by the new variant further squeeze staffing at hospitals, police departments, supermarkets and other critical operations struggling to maintain a full contingent of front-line workers.

To ease staffing shortages, countries including Spain and the U.K. have reduced the length of COVID-19 quarantines by letting people return to work sooner after testing positive or being exposed to the virus.

Delta CEO Ed Bastian was among those who have called on the Biden administration to take similar steps or risk further disruptions in air travel. On Thursday, the U.S. shortened COVID-19 isolation rules for health care workers only.

Additional reporting by The Associated Press.