All flights in and out of the Netherlands have been suspended as ash from a volcanic eruption in Iceland moves south.
The airspace restriction was the most significant in living memory, a spokesman said.
Norway, Sweden, Finland and Denmark were among the European countries hit.
The restrictions were imposed after the Met Office warned the ash was sufficient to clog engines.
Passengers were advised to contact their carriers prior to travel.
Experts have warned that the tiny particles of rock, glass and sand contained in the ash cloud would be sufficient to jam aircraft engines.