Finland’s national carrier Finnair Oyj canceled roughly 20% of its flights in February, in anticipation that staff sick leaves will continue to increase.

The move is intended to avoid last-minute changes and better manage customer expectations after a surge in absences tied to Covid-19 triggered scheduling chaos at U.S. airlines over the year-end holidays.

“The omicron coronavirus variant and flu season have led to a significant increase of sick leave” at the airline and with partner companies, it said in a statement on Wednesday. “Flight cancellations will enable Finnair to operate a more flexible schedule and adapt to the expected rise in sick leave.”

Most of the canceled services are on routes with multiple daily flights, including Stockholm, Oslo, Copenhagen, Paris and Rome, Finnair said.

With schedules already limited by border curbs, European airlines were able to avoid last-minute cancellations over the Christmas and New Year’s holiday. However, some restrictions are now being lifted, suggesting other carriers in the region may also face challenges with staff shortages.

Airlines in the U.S. entered the holiday season with schedules restored to levels approaching 2019. But thousands of flights had to be canceled after omicron swept through staff ranks and storms disrupted schedules.

Staff shortages have also plagued the travel industry in places like the Philippines and Mexico.