The IMPACT trade union has accused the IAG group of rehashing the current growth strategy of Aer Lingus management and using it as its own.
The union met with representatives of the group which is bidding to buy the former national flag carrier today.
However the body, which represents over 1,700 Aer Lingus staff, said it has heard nothing new and its concerns about jobs remain.
Spokesperson Matt Staunton said IAG Chairman Willie Walsh's jobs strategy is nothing new and not even his own.
"I heard Willie Walsh put on the shirt that the existing Aer Lingus management team use, that their transatlantic business is growing, and they should be able to put on an extra plane a year, and that will generate 100 jobs a year.
"He merely used the commitment and assessment that the existing management team have given."
Meanwhile, both the Tánaiste and the Minister for Enterprise have refused to say whether they support the sale of Aer Lingus.
Their party colleague Pat Rabbitte, said he thought missing out on the deal would be a mistake, in a column penned for the Sunday Business Post.
The Tánaiste, Joan Burton, said she will await a report from the Transport Minister before making up her mind.
"I think it's important that we get the reports and that we have to look at this in the round - in relation to what's in the best interest of Ireland, what's in the best interest of employment in Aer Lingus, [and] the future of aviation in the country," she said today.
Jobs Minister Richard Bruton said there is no need to be rushed into a decision, and that the Minister for Transport had "engaged serious expertise" to assess the sale.