Aer Lingus workers today threatened to strike if the Government proceeded with the proposed privatisation plan without consultation.
About two thirds of SIPTU members at the airline voted overwhelmingly in favour of industrial action in the event of any unilateral action by management.
SIPTU's National Industrial Secretary, Michael Halpenny said: "This result is clear evidence of our member's concern for job security, pensions and conditions of employment".
Mr. Halpenny said: "We have attempted to honour our promise to the Minister for Transport, Martin Cullen, on meaningful engagement with the airline and have detailed the concerns of our members to management.
"Regrettably to date, there has been an absence of meaningful engagement on the part of management and so we are no further on than we were four weeks ago," he said.
One of the core issues of concern among workers relates to the company's pension.
The airline says if current index-linked pension increases are to continue, a major deficit will arise, possibly up to €336 million.
Aer Lingus and Government officials have proposed using some of the capital generated from the sale of part of the airline to address its looming pension deficit.
Minister for Transport Martin Cullen has indicated that a decision on privatisation may be taken at Cabinet as soon as next week.