Budget airline Ryanair reckons it will able to persuade competition authorities that its latest bid for Aer Lingus isn't a cause for concern.
Chief executive Michael O'Leary said that his "remedies package" will be enough to satisfy the Competition Commission and remained confident that a deal is possible.
"There are 46 cross-over routes and we will remedy all of them by getting airlines to come to Dublin and take them over," he told a news conference in London. Mr O'Leary's airline launched a €694m (£550m) bid for Aer Lingus in June which the former Irish state carrier has urged its shareholders to reject.
The European Commission says "potential competition concerns" exist about the proposed takeover.
"Ryanair and Aer Lingus are the main operators out of Dublin Airport," it said. "On a large number of European routes, mainly out of Ireland, the two airlines are each other's closest competitors and barriers to entry appear high. Many of these routes are currently only served by the two airlines."
Ryanair said last week that its existing offer - priced at €1.30 (£1.03) per Aer Lingus share - has now lapsed under takeover rules due to the Phase II assessment.
"Ryanair's offer lapses, in accordance with takeover rules, with immediate effect, and all acceptances of the offer to date are void," it said.
"Ryanair intends to re-bid for Aer Lingus if the European Commission clears its offer following its Phase II review," the airline added. The European Commission blocked Ryanair's first effort in 2006.
Aer Lingus said that it was a "much stronger airline today" and claimed the reasons for rejecting the latest bid were even stronger than they were a few years ago.