Omicron forces Ryanair to double its annual loss forecast.
The emergence of the Omicron variant is believed to have caused travel restrictions in France and Germany.
The low-cost-carrier cut its January traffic estimate by a third. The December passenger forecast was cut from 10 million to 9 million.
The airline expects losses to rise from between 100m and 200m to a range of 250m-450m for the financial year ending in March.
As more scientific information becomes available on the Omicron variant, it will be next month before the February and March schedules are revised.
The budget airline said in a statement that the sudden emergence of the variant has weakened Christmas and New Year bookings.
The Chief Executive Officer of the airline made headlines earlier in the week when he said that passengers should only be allowed to fly if they are vaccine free.
He said that if you aren't vaccine-free, you shouldn't be allowed to go to the hospital, fly, or shop in the store.
