Aer Lingus craft and maintenance workers are to be balloted over proposals to end maintenance work at Shannon and close the hangar there.
The ballot will be carried out among staff at the country's three main airports.
The proposal means that 55 workers could face compulsory redundancy or be moved to Dublin.
Workers met with union representatives at the hanger in Shannon this afternoon to decide on what industrial action they might take as a result of the company's proposal.
Chairman of the Aer Lingus craft group of unions Brian Gormley said workers had decided on a "protective ballot".
Mr Gormley of UNITE said staff had been shell shocked by news of the proposal last month.
He added that they had come up with alternative cost cutting measures, but the company had given a very negative response to those.
He said maintenance workers at Shannon were determined the company could not walk away from its responsibilities.
