Bad weather in December that led to the closure of airports across Europe cost Air France-KLM an estimated €70 million.
The figure was double the level the airline had forecast last month, when it predicted weather-related losses of €25-35 million.
The carrier said: “The passenger and cargo activities were each affected by the periods of heavy snowfall in December in both Europe and the United States.
“Unit revenues rose slightly in passenger and more strongly in cargo. The impact on revenues of these weather disruptions is estimated at 70 million euros.”
Passenger numbers for the month dropped by 1.6% to 5.4 million, with medium-haul flights worst affected by cancellations.
The snow also hit the European network with traffic down by 1.1% and capacity cut by more than 6%.