Aer Lingus has rejected a takeover bid from IAG, the parent company of British Airways, Iberia and Vueling.
IAG, headed up by former Aer Lingus chief executive Willie Walsh, was eyeing up a takeover bid in order to gain valuable access to slots at Heathrow airport where Aer Lingus is the third biggest airline.
Reports of the bid led to Aer Lingus shares rising by nine per cent by the close of trading on Thursday (December 18).
Any deal would require the backing of Ryanair and the Irish government as both hold stakes in the company.
It would also need to approval of the regulators to ensure that competition was not threatened on certain routes.
IAG confirmed in a statement that the offer had been made and rejected but has made no further comment on whether a revised proposal would be forthcoming.