Ryanair carried 4.2 million passengers in February, down from the 4.47 million carried in February of last year.
Part of the decrease was due to Ryanair's decision to ground 80 aircraft, which accounted for a 3% drop in passenger numbers.
Another factor was the leap year last year in which February had 29 days as opposed to 28 days this year.
That resulted in a further 3% drop in passenger numbers.
The load factor in February increased by 1% in the year to 77%.
Ryanair also recorded a 4% increase in passenger numbers in the year to February 2013 of 79.3 million.