The board of Aer Lingus is expected to consider today a Ryanair request for an extraordinary general meeting of shareholders to discuss the Shannon-Heathrow controversy.
Informed sources said that Aer Lingus directors would be given legal advice obtained on the implications of the resolutions put forward by Ryanair.
Ryanair, which is the largest shareholder in Aer Lingus, has proposed that the meeting should effectively compel management at the former State airline to reverse its decision to end the Shannon-Heathrow service.
It has also proposed that existing Aer Lingus services to London Gatwick could be scaled back to facilitate the establishment of new routes from Belfast as well as the retention of the Shannon operation.
No decision has yet been taken by Aer Lingus regarding the timing of any extraordinary general meeting.
Informed sources said there were concerns in the airline that there could be implications under competition law, given that Ryanair could benefit commercially if its resolutions were passed. Ryanair currently competes with Aer Lingus on the Dublin-Gatwick route.
Meanwhile, talks between Aer Lingus management and representatives of the company's pilots continued yesterday at the Labour Relations Commission for a third day in the dispute over the airline's plans to establish a new base in Belfast.
The talks, which averted a threatened 48-hour strike by pilots last week, are scheduled to continue on Thursday and Friday.
Michael Landers, assistant general secretary of the trade union Impact, said that he was optimistic about the outcome.
However, other sources indicated that the parties were still quite a distance apart on the central issue of whether the union should have a role in negotiating conditions for pilots in Belfast.
Separately, Impact, which also represents cabin crew, has sought clarification from the Labour Court in relation to a recommendation it made in February on plans by Aer Lingus to establish bases outside the Republic. The court said that the airline should be allowed to recruit staff at local pay rates.
Impact has asked the court to clarify whether it had intended that its recommendation would include Belfast.
It also asked whether the court had understood that the opening of any new base would be at the expense of staff at existing bases. The court's response could have implications for the current talks.
Meanwhile, the Shannon Connectivity Alliance - which is campaigning against the Aer Lingus plan to close the Heathrow route - will today hold talks with EU competition and transport officials in Brussels.