Dublin Airport in Ireland handled only 1.6 million passengers in May when the volcanic ash crisis was on, a drop of 15% compared with the same period in 2009.
As a result of the airspace closure, the airport's passenger traffic dropped 9% with 100,000 fewer passengers passing through its gates.
European traffic fell by 12% to 865,000 passengers, passengers to UK dropped by 18% to 520,000, while Middle East numbers grew by 14% to 20,000 passengers.
Domestic traffic also declined by 49% to 30,000 passengers, while transatlantic traffic to North America fell by 8% to 130,000 passengers.
The airport has handled 6.7 million passengers year-to-date, a drop of 18% over the same period in 2009.