Kenny Jacobs, chief marketing officer at Ryanair, commented: "Regrettably, nearly 200,000 Ryanair customers had their flights cancelled in July because of repeated ATC staff shortages in the UK, Germany and France, adverse weather, and unnecessary pilot and cabin crew strikes".
Pilots in Belgium and Sweden have announced a walkout for Friday, August 10.
Trade union Forsa, of which the Irish Air Line Pilots' Association (IALPA) is a branch, said directly employed Ryanair pilots in Ireland would stage their fifth one-day strike since July 12 beginning at 0100 on August 10 in an ongoing dispute about working conditions including base transfers.
The airline is bracing itself for another round of strike action next Friday, when 25 per cent of its pilots will strike.
It is not yet clear how many flights and passengers will be affected by the industrial action.
Last month, the budget airline criticised the strikes as unnecessary and warned that, if they continue, there could be job losses.
A month earlier in a memo seen by Reuters Ryanair said time-off duties for the pilots committee remained an issue but there was little between the two sides and it was hopeful of a deal.
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Forsa said the striking workers continue to seek a "fair and transparent" way of governing base transfers and related matters which they say is common practice in the industry.
Ryanair, which operates from 86 bases in 37 countries and carried 130 million passengers last year, made a decision to recognise unions for the first time in its 32-year history last December to avert widespread strikes before Christmas.
"The airline's escalation of the dispute when it threatened to sack 100 pilots and 200 cabin crew, or transfer them to Poland, led to a predictable hardening of resolve among its staff".
The first strike was followed by two more one-day strikes on July 20 and July 24.
Below are a list of the strikes that have taken place or are planned since union negotiations began.
Ryanair cancelled dozens of flights to and from airports in Portugal when cabin crew union SNPVAC staged three one-day strikes on March 29, April 1 and April 4.
However, the union reiterated that it remains open to talks and is even prepared to explore the option of third-party facilitation - which to date has been ruled out by Ryanair.