Figures from Aer Lingus show that it carried just over one million passengers in July, a drop of 8.7% from the same month last year.
But the load factor, or percentage of seats filled, rose by 3.5 points from July last year to 85.8%.
Passenger numbers on short-haul routes fell 8.3% to 921,000, while the figure for longer routes dropped 12.4% to 99,000.
The load factor on Aer Lingus's long-haul routes rose sharply - by 12.8 points to 89.8%. This was helped by a cut of almost 28% in routes and flights over the past year. The load factor on short-haul routes dipped 1.6 points to 84%.
For the first seven months of 2010, passenger number are down almost 10% to 5.6 million, though the load factor is up 1.9 points to 77.3%.
