Ryanair has urged Europe to step up the "slow pace" of COVID-19 vaccinations as it reported a €321m (£279m) loss for the Christmas quarter.
The Dublin-based carrier said the EU needed to try to match the performance of the UK in rolling out jabs against the virus which it said "continues to wreak havoc across the industry".
Latest restrictions pushed traffic down by 83% to 1.9 million passengers in December compared to the same month a year earlier, Ryanair said.
For the third quarter to 31 December as a whole numbers were down by 78% to 8.1 million and revenue fell by 82% to €340m (£296m).
Ryanair's loss for the quarter compares to a profit of €88m (£76m) in the same period a year earlier.
With lockdowns and test requirements expected to take their toll on flight schedules through to Easter, the airline - which is Europe's biggest - has reduced its outlook for passenger numbers for the full year to the end of March.
But Ryanair, seen as one of the carriers best placed to navigate through the pandemic, expects to capitalise through growth in places where rivals have scaled back or failed during the crisis.
It said: "We take some comfort from the success of the UK vaccine programme which is on target to vaccinate almost 50% of the UK population (30m) by the end of March.
"The EU now needs to step up the slow pace of its rollout programme to match the UK's performance."
The airline said it expected to report a full-year loss of €850m-€950m (£740m-£827m), by far its biggest ever, and that it "will continue to be the most challenging year in Ryanair's 35-year history".
