It comes as Dublin-based pilots prepare for their fourth strike day tomorrow
Ryanair has said tomorrow's strike by Dublin-based pilots is likely to go ahead, as it warns of potential 'coordinated' pilot strikes in Europe next week.
The airline says it has received notice of action next Friday by pilots in Sweden and Belgium.
Yesterday, the Swedish Airline Pilots Association (SweALPA) said it called the action because the airline had consistently refused to meet with its representatives without preconditions.
Belgian pilots, meanwhile, accused Ryanair of 'unacceptable' practices that "go against the right to strike, which is a fundamental right guaranteed by all international conventions".
In a statement yesterday evening, the airline said pilots in Germany and the Netherlands could also down tools on the same day.
Ryanair said: "We have written to each of these pilot unions today and invited them to meet us in the coming days to make further progress in concluding Union Recognition and Collective Labour Agreements in each of these markets.
"In the interim, we have requested these pilot unions to give us 7 days' notice of any planned strike action so that we can notify our customers of cancelled flights in advance and offer them alternative flights or refunds."
Ryanair pilots based in Britain have also taken a step towards industrial action.
Meanwhile, around 25% of the company's Dublin-based pilots are due to take part in their fourth strike day tomorrow.
The airline has cancelled 20 Irish flights, with 3,500 passengers affected, ahead of tomorrow's action.
It added that it hopes to meet pilots' union Fórsa next week for fresh talks, amid the ongoing dispute over issues such as seniority and base transfers.