Ryanair flights on its routes to Charleroi have been cancelled because of strike action at the Belgian airport.
Workers at the airport, which is often used by Irish passengers travelling to Amsterdam in Holland, are protesting against the plans to raise the age for early retirement from 58 to 60.
There could be further problems at the airport on Friday when a nationwide strike against the government's plans is due to take place.
Charleroi is Ryanair's European hub and a message on its website today apologised to customers and said flights can be rebooked free of charge until 16th November or claim a refund.
The strike affects two flights from Dublin airport as well as flights on its Milan Bergamo and Rome Ciampino routes.
"Charleroi is very much affected by unemployment and that is why they have decided not to wait until Friday to take strike action," a spokeswoman for the Christian trade union ACV/CSC said.
Charleroi, a victim of the decline of Belgium's steel and coal industries, has one of the highest unemployment rates in the country.
Additional reporting Reuters