FMDFM seek flight assurances over Aer Lingus takeover bid
The first minister and deputy first ministers want "legal assurances" that Belfast to Heathrow flights would be protected if IAG buys Aer Lingus.
IAG owns British Airways, which, like Aer Lingus, operates daily flights between Heathrow Airport and George Best Belfast City Airport.
Talks are ongoing and involve the Irish government which controls a 25% stake in Aer Lingus.
IAG has put forward a 1.36bn euros (£1bn) takeover offer for Aer Lingus.
By acquiring Aer Lingus, IAG would gain more take-off and landing slots at Heathrow - valued at around £30m per pair - allowing it to operate more flights.
The Northern Ireland Executive is anxious that Belfast's connectivity with Heathrow is protected.
Peter Robinson and Martin McGuinness said: "The Belfast to Heathrow landing slots are essential for our economic development.
"We would urge any potential buyer and everyone involved in the sale to provide legal assurances existing air links to and from Belfast will not be impacted as part of the proposed takeover.
"The capacity to attract and retain jobs would be jeopardised by any plans to use the existing slots from Heathrow to Belfast for other destinations."
The Irish government is currently looking at a revised offer for the airline from British Airways owner IAG.
The Aer Lingus board has said it is prepared to accept an offer worth 2.55 euros (£1.90) a share from IAG, in its latest takeover bid.
An acquisition would rest on the backing of the government as well as Ryanair, the other major shareholder.
The Irish government has a 25.1% share in Aer Lingus, while Ryanair has a 29.8% stake in the airline.
The Irish Airline Pilots Association has a seven per cent share in the airline.
Aer Lingus directly employs 3,900 people, mostly in Dublin, with 2,100 of these described as ground staff in areas such as clerical, operative and back office roles.
The airline is the fourth-largest operator at Heathrow after BA, Lufthansa and Virgin Atlantic.
Aer Lingus had rejected two previous IAG offers - pitched at 2.30 euros and 2.40 euros a share.
Ryanair built its stake in Aer Lingus as part of three failed attempts to buy the carrier.
Competition regulators blocked the takeover bids and told Ryanair it must sell all but 5% of its shareholding. However, an immediate sale was delayed by a lengthy appeals process.