Benign weather over Christmas and the probable impact of a burgeoning diaspora saw Aer Lingus carry 4.5pc more passengers in December than it did in the corresponding month during 2011.
Figures released by the airline show that its passenger numbers rose to 651,000 last month, with long-haul traffic jumping 13.4pc to 76,000. Short-haul passenger numbers rose 3.4pc to 575,000.
Aer Lingus cut its capacity by 2.5pc between December 2011 and last month.
The load factor, or percentage of seats filled, rose 2.9 percentage points to 70.9pc overall.
Short-haul load factors added 0.7 of a percentage point to 66.6pc, while long-haul rose 6.1 percentage points to 77.7pc.
Analyst Donal O'Neill at Goodbody Stockbrokers described the Aer Lingus figures as "strong" and said the data continues recent trends seen at Aer Lingus and most of its peers.
Shares in the carrier were unchanged at €1.16 in early afternoon trading.
Rival Ryanair also reported traffic figures yesterday. It said that it carried 4.84 million passengers in December, 2pc more than it did in the corresponding month in 2011. Its shares were nearly 3pc higher by early afternoon, at over €5.10.
Ryanair has also dismissed an allegation by Scandinavian airline SAS that the Irish carrier is deliberately under-reporting the weight of its aircraft in order to reduce its landing fees.
SAS filed a formal complaint to the Scandinavian aviation authorities in November.
It has claimed that Ryanair provides inaccurate aircraft weight data to Eurocontrol, the European aviation agency.
Air France has also accused Ryanair of the practice. Ryanair has insisted it complies with weight standards.