Aer Lingus has said flight cancellations due to the industrial dispute with the IMPACT cabin crew union and weather related disruption meant the number of passengers carried was 4% below the number who had booked to fly with the airline.
Aer Lingus says 552,000 passengers were booked to fly in January, which means just over 22,000 had their flight cancelled.
The airline said its total passenger numbers fell by 17% to 552,000 last month from 665,000 in January 2010.
Short-haul booked passengers were down over 17% to 504,000 while long-haul booked passengers fell 15.8% to 48,000.
Its booked load factor - how many seats it fills on each flight - decreased by 3.6 percentage points to 63.8%. The short-haul load factor eased by 4.8 percentage points to 62.8% with capacity falling by 15.2% as a result of the industrial dispute and planned reductions at Belfast, London Gatwick and Cork.
The airline's long-haul load factor decreased by 1.3 percentage points to 65.7% with capacity falling by 14.2% due to weather related disruptions, planned cuts at Shannon and the cabin crew dispute.
