European Commission aborts Ryanair's bid for Aer Lingus

"We look forward to the European Court's overturning this unprecedented and unlawful prohibition," O'Leary said at a press conference in Dublin.

Earlier at a press conference in Brussels on Tuesday, O'Leary had criticized the Commission's "nakedly political decision," claiming it reversed 20 years of airline consolidation and comes amid a vendetta against Ryanair. The European budget carrier has come under Commission scrutiny for subsidies paid to the airline at Belgium's Charleroi airport.

According to Ryanair, this is the first time that the Commission has prohibited a merger between two companies which, combined, will have less than 5% of the EU market. It said that this was also the first time that the Commission had prohibited an airline merger.

Ryanair made its bid for Aer Lingus in October last year, just one week after the national carrier debuted on the London and Dublin Stock Exchanges. The offer lapsed in December with the EC starting an antitrust probe.

Defending the Commission's decision, Neelie Kroes, the European Union's competition commissioner, said that combining Ireland's leading carriers would have "dramatically reduced choice for consumers," leading to higher prices for the more than 14 million passengers who travel every year.

Earlier, Kroes had said in Brussels that the Commission "…did not prohibit mergers lightly, but in this case the Commission has no alternative."