Staff at Aer Lingus and the Dublin Airport Authority have voted for industrial action in a row over pensions.
Six trade union groups representing airport workers - SIPTU, Impact, Mandate, the TEEU, Unite and UCATT are now mandated to serve notice if either company attempts to make changes to their pension scheme without the agreement of staff.
The Irish Aviation Superannuation Scheme has a deficit of around €700m.
Liam Berney from the Irish Congress of Trade Unions said the travelling public would not be immediately affected, but added the unions wanted a speedy response from management.
"That window of opportunity is about two or three weeks…If in that period of time we haven't heard from the employers as to what they are prepared to do, I suppose we would have to consider the position then," he said.
"I don’t envisage...any immediate threat to the travelling public."