There is speculation this evening that Aer Lingus cabin crew may join pilots in the dispute with management over the establishment of a new base in Belfast.
This follows confirmation from Impact, which represents pilots and cabin crew, that it has written to the Labour Court querying whether its recommendation on "foreign bases" was meant to include Belfast.
The recommendations, issued last February, said that management should be allowed to recruit staff in foreign bases at local pay rates.
But Impact today published details of a letter of enquiry sent to the Labour Court on August 21st which sought clarification on whether its recommendation on foreign bases was intended to include Belfast.
The union also asked whether the Labour Court understood that the opening of any new base would be at the expense of staff at existing base.
The Court has written to Aer Lingus asking for its observations in relation to Impact's enquiry and has promised to reply to the union's letter once it has received the airline's response.
The move has fuelled speculation that Aer Lingus cabin crew may join pilots in their opposition to management's plan to hire pilots for Belfast on inferior terms to Dublin-based pilots.
Meanwhile management and union representatives were back before the Labour Relations Commission (LRC) today for talks over the airline's new Belfast base.
Discussions on the row, which had threatened to ground the airline's fleet for two days last week affecting around 40,000 passengers, were adjourned at the LRC last Wednesday afternoon.
The dispute centres on whether the Irish Airline Pilots' Association and Impact should have a role in negotiating the pay and conditions for pilots recruited at the new Northern Ireland base.
The union claimed pilots recruited in Belfast would be on worse terms and conditions than those that apply in the Republic.
But the airline insisted pilots would get higher salaries at the early part of the pay scale, although they would not be allowed participate in the defined benefit pension scheme.
Aer Lingus said unions could not be involved in talks on bases outside the Republic.
The pilots' union said last week they were optimistic a solution could be found to resolve the disagreement. Further talks are also scheduled for Thursday and Friday.
City councillors in Limerick are expected to meet later today to consider formally boycotting the airline because of its decision to end the Shannon-Heathrow route.
The Aer Lingus board is also to meet on Wednesday to consider Ryanair's demand for an EGM of shareholders to have the decision reversed.
It is believed that the airline's directors will ask the Government, which holds 25 per cent of Aer Lingus shares, to vote for ending the route in an effort to ensure the failure of Ryanair's motion at the EGM to overrule management and save the route.
A delegation of industry and tourist interests from the West and Mid-West, led by Fianna Fáil TD for Clare Timmy Dooley tonight travelled to Brussels to explore all options at EU level towards achieving a resolution to the Shannon
The delegation, which was put together in recent days by the Clare Dail Deputy, will include representatives of the business and tourism sectors affected by the Air Lingus decision to end the Shannon-Heathrow service.