Siptu has accused the Aer Lingus executive of "underhand tactics" after reports the airline's bosses were seeking a management buy-out.
The union, which represents most of the State carrier's workers, also said it would vigorously fight any attempt to impose further job cuts and labelled the executive's buy-out bid as "unprecedented" and a rejection of the social partnership agreement.
Siptu's Aer Lingus branch secretary, Mr Christy McQuillan poured cold water on reports that up to 1,300 jobs could go at the State airline, claiming that it was "questionable whether the company could continue to operate" if yet more swingeing cuts were piled on top of the 3,000 redundancies achieved over the last three years.
He said Siptu is already dealing with 102 scheduled job losses at Shannon but claimed axing positions at the company's freight and catering division - where there are 240 staff employed - was "entirely unexpected" and accused the management of fobbing off the union in its latest business strategy.
"It's a total fob-off," he said. "We've been waiting for the last seven months for the company to tell us exactly how they were planning on achieving the costs cuts targeted in the 2004 business plan, only to be told a three-year business plan was under way which would subsume this year in full.
"Then over the weekend they come out with this management buy-out proposal. It all flies in the face of the social partnership model."
Despite what Mr Maquillan describes as "growing anger" amongst workers at the management's buy-out proposal, he ruled out any possibility of strike action, claiming employees had sacrificed too much in turning Aer Lingus around to "jeopardise the company's finances in such a manner".
Mr Maquillan said the union is instead organising a "three-airport strategy committee" that was originally formulated, "as a central platform to negotiate the anticipated three-year business plan, but will now deal with the weekend's developments."
He said the union is looking for early engagement with the Minister for Transport, Mr Brennan, on the latest proposals from the company's management and claimed "any future changes at the company wil have to be discussed with all parties".
He also said the union was now wary of negotiating with the Aer Lingus executive after the weekend's buy-out bid strategy and the stalled hand over of a 14.9 per cent stake in the company due to workers under the 2002 annual report.