The Irish airline on Friday said that more than 2,150 of its 2,400 scheduled flights would operate as normal.
Ryanair, which initially cancelled 150 flights due to what it said was an unnecessary strike by a "tiny minority of cabin crew", cancelled up to 100 more on Thursday after German pilots said they would join the protest.
All affected customers received email and text message notifications on Tuesday to advise them of cancellations and options, Ryanair said.
In Tenerife, Spain, hundreds of passengers queued at Ryanair counters and dozens more at the Madrid airport as 86 flights of the low-priced company from or to Spain were cancelled, affecting some 16,000 passengers, according to Spanish unions.
The astonishing revelation comes on the same day that other furious passengers claimed that the Irish budget carrier was cancelling flights just hours before take off today.
"We sincerely apologise to those customers affected by these unnecessary strikes on Friday which we have done our utmost to avoid", Ryanair said.
Staff claim this creates huge insecurity for them, blocking their access to state benefits in their country.
The subsequent decision to start recognising pilot and cabin crew unions around Europe was a multinational can-of-worms.
In Portugal, 13 morning flights were cancelled and in the Netherlands, 14 of 22 flights were cancelled.
"Respecting EU law is not something over which workers should have to negotiate, nor is it something which can be done differently from country to country", Ms Thyssen said. "This is not an academic debate, but about concrete social rights of workers".
Boss Michael O'Leary, who survived a shareholder rebellion last week but faces increasing pressure from investors, said the company had written to unions offering to move all staff to local contracts, which made the strike action "unnecessary".
On Thursday, the airline said it would base two aircraft in Bordeaux and two more in Marseille, using the airports as a hub to add 27 new routes to its northern summer 2019 schedule.
"It is inexplicable that the VC Union can not explain why they are calling a strike to agree a CLA when Ryanair has already agreed in writing to arbitration in Germany, which will complete a German CLA by the end of October for the benefit of our pilots in Germany", Bellew said.