Ryanair has rejected a claim that a number of cabin crew based in Spain have lost their jobs for exercising discretion not to fly due to fatigue.
A spokesperson for the union SNPVAC claimed that four members of cabin crew, resident in Mallorca, had lost their jobs because they "executed their responsibility to refuse to keep going due to fatigue" earlier this month.
The spokesperson said the crew had called fatigue after completing three of four flights on 8 July and were initially suspended.
It follows a memo issued to cabin crew by Ryanair head of inflight Andrea Doolan.
The memo stated that in recent weeks, a number of cabin crew had refused to complete their duty "... on the uninformed assumption that they have 'discretion'".
It is understood the row arose after some cabin crew argued after a long day that they were "out of hours" and that it would be unsafe for them to fly, leading to a flight being unable to depart.
The memo said that on the rare occasion where there is an issue of operating into discretion, only the commander of the aircraft can exercise that discretion, and that instructions from the operations department must be carried out.
It said that due to cabin crew rostering the issue of fatigue arises very rarely and was not a factor in any of the recent events.
In the memo, Ms Doolan said that Ryanair would not allow passengers' travel plans to be disrupted because a tiny number of cabin crew refused to operate flights
She warned that any such refusals would be dealt with through disciplinary procedures up to and including dismissal.
In a tweet yesterday, Ryanair stressed that the memo specifically dealt with cases of refusal to fly where long hours or fatigue did not arise.
Today, the airline said the claim by the union, that cabin crew who had exercised discretion over whether to fly due to fatigue had lost their jobs, was not true.
Ryanair said that no cabin crew had lost or could lose their jobs over discretion.
The development comes as cabin crew based in Spain, Portugal, Italy and Belgium prepare to take industrial action on 25 and 26 July.
Ryanair has pledged to inform customers about potential disruption to travel plans when they have full details of two further pilot strikes planned for later this month.
More than 5,000 Ryanair passengers planning to travel yesterday had their plans disrupted by the strike of directly employed Ryanair pilots.
Things are set to get even worse after pilots' union Fórsa announced two further 24-hour stoppages during the peak of the summer season - on Friday 20 July and Tuesday 24 July.
All this means huge uncertainty for Ryanair customers who have flights already booked, as well as future travel plans.
For airline management, there is yet another challenge of rerouting planes and passengers to minimise disruption.
Ryanair said that if the pilots wanted to stage more unsuccessful strikes, so be it. However, it said it remained available for talks.
The airline advised pilots to sign up for a working group with the union to negotiate issues in dispute.
Fórsa said it was regrettable that Ryanair management had so far rejected the suggestion of third party assistance to break the deadlock.
As of now, no further talks are scheduled.
Additional reporting: Ingrid Miley