THE scale of the challenge facing Ryanair in appealing the European Commission's decision to block its bid can't be understated.
The carrier's first bid to buy Aer Lingus was rebuffed by the Commission and so too was the subsequent 2007 appeal to the General Court of the European Union in Luxembourg. It denied Ryanair's appeal in 2010, but also said at the time that Ryanair couldn't be forced to sell its Aer Lingus stake.
If Ryanair's latest planned appeal proves successful, it would be the first time in more than a decade that an EU anti-competitive ruling has been overturned. The fresh appeal would, as with the first one, take years.
It would also likely scare off other strategic investors and stymie the Irish Government's efforts to offload its own 25.1pc – part of a package of privatisations required by its €85bn EU-IMF bailout.
"The Government and Aer Lingus will simply have to wait and see what Ryanair chooses to do," said analyst David Holohan at brokerage Merrion Capital. "Until the Ryanair process is completed, I think the Government will struggle to find a buyer."
A €700m-plus pension deficit that serves Aer Lingus and DAA workers is also another possible spanner in the works.
Until it's resolved with unions, the government stake – and interest from any other potential Aer Lingus suitor – remains firmly in limbo.
Michael O'Leary has already said he would consider selling the Aer Lingus stake if the latest bid was blocked. Ryanair could target institutional investors keen to get exposure to one of Europe's few profitable airlines and sell its stake that way.
Aer Lingus made a €69.1m operating profit last year, up 41pc on 2011, but cost-cutting and savings rather than any real growth have been key to improving the bottom line.
Dropping Ryanair would also clear the way for a large industry investor with deep pockets, like minority shareholder Etihad, or boost the company's "free float" of readily tradeable shares, which Aer Lingus believes would help lift its share price.
Aer Lingus's best hope of ridding Ryanair from its share register may be a probe by Britain's Competition Commission into whether the Ryanair holding distorts competition in the UK market.
The investigation has been delayed by the European probe and even if it is restarted, Ryanair could likely use appeal processes to delay a final decision for more than a year.