Ryanair says it carried 5.7 million passengers in March, an increase of 8% on the same month last year.
The load factor - the percentage of seats filled - was unchanged at 79%.
Last week, Ryanair announced that it would charge a €2 levy on each passenger from today, claiming the move was a result of costs imposed on it by EU rules.
The airline said it had incurred costs of more than €100m over the past year from flight cancellations, delays and providing rights such as meals and refunds to passengers hit by disruption.
