Aer Lingus passenger numbers rose by 15 per cent last month on the back of additional capacity, the airline said today.
However, following the acquisition of aircraft and the addition of routes, Aer Lingus said its load factor, or proportion of seats filled, dropped from 68 per cent, compared with 72.6 per cent in December last year.
Overall passenger numbers increased by 9.6 per cent to 695,000 people.
On long-haul flights, the load factor dropped by 9 percentage points to 71.4 per cent.