AER Lingus has been hit with a fresh threat of industrial action after talks over a pensions row broke down.
Siptu and Impact trade unions will meet on Tuesday to decide what action to take in the run-up to Christmas after negotiations collapsed at the Labour Relations Commission (LRC).
Aer Lingus said it has not been put on notice and does not anticipate disruption to the schedule at this point in time, but will communicate with customers accordingly if this situation changes.
However, Siptu organiser Dermot O'Loughlin claimed they were left with no choice but to consider industrial action, up to work stoppages, to end the dispute.
Cabin crew and ground, clerical and administration staff will take part in any action from as soon as November 6, he warned.
"It is disappointing that there has been no progress in the discussions to resolve the crisis which threatens thousands of employees with financial ruin in their retirement years," he said.
"The intransigence of Aer Lingus is particularly disturbing as the airline is responsible for its failure to properly fund the pension scheme over many years."
The dispute centres on the Irish Airlines Superannuation Scheme, a pension pot which was in deficit by some 700 million euro (£557 million) at the end of last year.
Travel chaos at the country's main airports was averted last month when unions and management at Aer Lingus and Dublin Airport Authority (DAA) agreed to enter talks.
While negotiations are continuing with DAA, industrial trouble-shooters last night adjourned the talks with Aer Lingus indefinitely as the parties disagreed on the amount of cash offered.
However Ryanair, which owns almost 30% of Aer Lingus, said it supports the former state carrier's stance and would supply aircraft in the event of a strike.
"Ryanair will provide every assistance to Aer Lingus to maintain competition with Ryanair, and defeat these threats of disruption to Aer Lingus schedules by Aer Lingus unions who are yet again seeking to unjustly enrich themselves at the expense of Aer Lingus' shareholders," said spokesman Stephen McNamara.
It also called on the DAA to dismiss any further attempt by its unions to "featherbed" their pension schemes, as any cost increase will inevitably be passed on to passengers.
"A strike by Aer Lingus cabin and ground crew could cause untold damage to both the tourism industry while there would be a huge knock-on effect to the economy as well," he said.
"We are heading into the busy Christmas period and a November strike by Aer Lingus could dissuade much of our diaspora from returning for Christmas."