Ryanair said this morning it plans to sue the European Commission for failing to take action over complaints about state aid for a number of rival airlines.
Ryanair said it made complaints involving Air France, Lufthansa, Alitalia and Olympic Airways and that these were submitted to the commission over a year ago.
Last month, the European Commission prohibited Ryanair's proposed €1.5 billion takeover of Aer Lingus, arguing that it would harm consumers.
In a decision published on June 27th, the commission concluded that the merger would have created competition concerns on at least 35 routes operated by both companies.
"Our decision to prohibit this merger was essential to safeguard Irish consumers, who depend heavily on air transport," said competition commissioner Neelie Kroes.
"Monopolies are bad for consumers because they reduce choice, lower quality and give rise to higher prices. Low cost carriers like Ryanair are not exempt to this rule."
Ryanair has a 25.2 per cent stake in Aer Lingus.
Aer Lingus had hoped the commission would force Ryanair to sell its stake, and it may be forced to complain to the Irish Competition Authority to seek this action now.