British Airways’ parent IAG blamed the November terrorist attacks in Paris for an increase in empty seats on its flights in December.
The group, which includes Iberia, Aer Lingus and Vueling, also claimed the attacks in the Paris capital led to a drop in first and business-class travel.
IAG saw a 0.6 percentage point fall in its load factor to 78.6%, while its premium traffic was down 0.3%.
Overall, the airline saw a 10% rise in traffic in the year to December, and traffic that month was up 5% over December 2014.
The company said its guidance for full year 2015 operating profit, issued with its third quarter results, remains unchanged.
