The European Commission has cleared the €1.36bn takeover of Aer Lingus by IAG.
It means the deal is now almost certain to go ahead.
Aer Lingus shareholders will vote on the takeover tomorrow.
Shareholders including the Government, Ryanair and Etihad have already given their support to the acquisition.
The commission said it had some concerns that the merged airlines would face insufficient competition on some routes and could have prevented Aer Lingus connecting onward passengers to competing airlines.
However, IAG is providing a number of commitments in order to secure take-over approval, European Commissioner in charge of competition policy Margrethe Vestager said.