Strike action will go ahead as planned today after Ryanair lost its High Court bid to force its pilots to take to the skies.
A judge sitting in London on Wednesday rejected an urgent application by the airline for an injunction against the British Airline Pilots' Association (Balpa).
Following the court victory, Balpa said it had offered to reopen talks with Ryanair in a last ditch attempt to avoid industrial action.
But the union said the airline had "rejected the offer out of hand" and that the strikes will go ahead as planned between 00.01am on Thursday until one minute before midnight on Friday.
Brian Strutton, Balpa general secretary, said: "Ryanair foolishly tried to stop our strike in the High Court today and failed.
"Despite that, we extended an olive branch to Ryanair as a way of getting back around the table and calling off strikes over the next two days.
"We are extremely disappointed that Ryanair have taken such a belligerent and negative stance.
"We have become used to their macho posturing, but sadly it is their passengers who will pay the price for Ryanair's attitude."
A second round of strikes is planned between September 2-4.
Just a few hours before the judgment in London, Ryanair won a similar legal move at the High Court in Dublin, meaning flights departing from Irish airports will operate as normal.
The airline urged the Forsa union, and what it described as "this small minority of very well paid Irish pilots" to resume mediation.