Ryanair and Aer Lingus say a number of flights to and from France today were disrupted due to a strike.
Air traffic controllers in France are among public service workers involved in industrial action.
A number of flights were delayed today while there were also some cancellations.
The strike is due to end at 6am tomorrow morning.
Eurocontrol warned of "extensive delays" across the whole of France, especially in the south and west of the country.
Flights that fly over French airspace are also liable to be affected in the strike.
Further disruption is expected tomorrow and passengers are advised to check-in on time and to check with their airlines for more details.
