Aer Lingus has announced it is to leave the Oneworld Alliance as part of its attempts to develop a new long-haul strategy.
The decision to leave the alliance, whose members include American Airlines, British Airways and Qantas, was approved at the airline's board meeting last week. Aer Lingus joined the Alliance in June 2000.
In a statement, the airline said its business strategy has changed fundamentally since them and Aer Lingus "has successfully repositioned itself as a profitable low fares point to point carrier".
It said it has introduced 48 new routes since 2000 and connecting passenger numbers to and from partner airlines have declined by over 50 per cent.
"Alliance membership has inevitably become less relevant for the airline over time," Aer Lingus chief executive Dermot Mannion said.
Mr Mannion said discussions are under way to ensure Aer Lingus can maintain "strong bilateral relationships with our existing Oneworld partners".
Since his appointment as Aer Lingus chief executive, Mr Mannion has made new long-haul routes his goal. This approach has the backing of the Government, particularly Minister for Transport Martin Cullen.
His predecessor, Willie Walsh, considered leaving the alliance last year, but fellow chief executives persuaded him to remain.