Disruption caused by last month’s severe weather has been estimated to have cost British Airways £50 million.
December traffic was down by 8.3% compared with the same month a year earlier as operations were hit by the snow and ice.
The conditions caused thousands of BA flights to be cancelled, with many UK, European and North American airports forced to shut.
The number of passengers carried in December fell to 2.1 million from 2.4 million in December 2009 after airport closures and fight cancellations meant it had 12% less capacity.
“An initial assessment indicates that the weather disruption will have a financial impact in Quarter 3 of some £50 million, with some small additional impact in January from cancelled return journeys,” the airline said.
The potential £50 million bill will be a blow to the airline which recorded its first half-yearly profit in two years during the half year to the end of September.
But the impact is less than £108 million in costs suffered as a result of flights being grounded by the ash cloud from the Icelandic volcano last year.
Strikes by cabin crew last summer cost BA about £142 million. Separately, BA confirmed a deal for Rolls-Royce engines for its Airbus A380s on order.
The contract, initially announced in 2007, could be worth more £3.2billion, Rolls-Royce said. The confirmation comes after a Rolls-Royce engine on a Qantas A380 exploded last month, forcing an emergency landing in Singapore.