Latest: Ryanair passengers are facing even more disruption after pilots in Belgium announced that thye will hold a strike on August 10.
It is the same day as Swedish pilots hold their strike and makes it the fourth country where pilots are taking industrial action.
The German pilots union VC has also backed strike action, while Irish pilots are set to hold their fourth day of strikes on Friday.
Yesterday, pilots based in the Netherlands voted by almost 96% to back strike action.
Earlier: Ryanair pilots in Sweden to hold strike on August 10
Ryanair pilots in Sweden have announced they will strike on August 10, the Swedish Pilot Association (SPF) says.
The 24-hour strike will be held due to disagreement between the union and the airline over collective agreements and pilot contracts, which are currently on an individual contract basis.
According to Swedish newspaper Expressen, the strike will apply to about 80% of Ryanair's pilots in Sweden which equates to more than 40 union members.
"We of course hope this means Ryanair come to the negotiating table. Should it not have any effect we will consider further action," SPF chairman Martin Lindgren told news agency TT.
Mr Lindgren told Expressen: "But Ryanair has consistently refused to meet the SPF with the representatives of the association we choose.
"There have been restrictions on who can participate in the negotiations from our side, and of course we can not accept that," he said.
Ryanair said in a statement: “We have written to each of these pilot unions in recent days and invited them to meet with 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 minimise the disruption to our customers by cancelling flights in advance and offering them alternative flights or refunds.”
Meanwhile, Irish pilots will hold their fourth day of strikes on Friday, August 3.
In a statement this morning, Ryanair called on the FORSA union to respond to its latest invitation to meet after the airline agreed to nine of the 11 requirements.
They said they wanted to meet union representatives to "get down to the serious work of resolving this dispute".
Regarding Friday's upcoming strike, 20 out of 300 Irish flights have already been cancelled and 3,500 passengers have been re-accommodated but Ryanair says "the damage has been done by this strike and cannot be reversed".
Ryanair calls on FORSA to respond to latest invitation to meet (sent Monday) and avoid further strike action after Ryanair agrees to 9 of 11 requirements: pic.twitter.com/LMJjpGXF7V— Ryanair (@Ryanair) August 1, 2018
There was further cause for headache among Ryanair bosses yesterday when pilots based in the Netherlands voted by almost 96% to back strike action.
There were also delays to 55 flights this morning as a result of shortages of German and Spanish air traffic controllers.
According to Ryanair, 13% of their 440 first wave of flight departures were affected.
"We sincerely regret these unjustified delays and are doing our utmost to limit their impact on flights throughout the rest of today," Ryanair said in a statement.
ATC Update - August 1st: pic.twitter.com/V3BrGJvlSY— Ryanair (@Ryanair) August 1, 2018