Ryanair has accused the pilots' union IMPACT of costing each of its pilots up to €80,000 in lost wage increases and share options by pursuing a failed case on behalf of members.
The airline's director of human resources Eddie Wilson accused the unions of chickening out of a Labour Court hearing on their complaints.
He was speaking at the Labour Court, where a scheduled hearing on complaints by Ryanair pilots had been cancelled in the wake of a Supreme Court ruling in favour of the airline.
For over three years, IMPACT and IALPA tried to use 2004 legislation to pursue pilots' complaints against Ryanair, which does not recognise unions.
But last February, the Supreme Court ruled that Labour Court procedures were unfair, and ordered a re-hearing with more appropriate procedures. A fortnight ago, the unions announced that they would not participate in the re-hearing.
It is understood they were advised that, following the Supreme Court judgement, it would be almost impossible for them to win their case.
Despite the fact that there was no hearing today, Ryanair sent a delegation to the Labour Court - including two people dressed as chickens.
Director of human resources Eddie Wilson accused the unions of chickening out of the hearing.
Replacement legislation on union recognition will now be a key union demand in the upcoming national pay talks. But the challenge for them is to ensure that any new laws do not contain further unintended landmines.