One of the most senior managers working for Aer Lingus at Dublin airport has left the airline and joined low-cost rival Ryanair.

Adrian Dunne was Aer Lingus Dublin station manager for several years, which is regarded as one of the most senior roles at the airline.

It is understood he will have a major operational role with Ryanair and will work closely with chief executive Michael O'Leary. He left Aer Lingus on August 12th.

Neither airline would comment on the defection yesterday, but sources at Aer Lingus said it had become relatively rare in recent years for senior management to move between the airlines.

Mr Dunne has been working in a range of areas for Aer Lingus over the past few years, including passenger services, ground handling and check-in.

In more recent times he was centrally involved in the introduction of the airline's FastPass self-service check-in facility. Last night, colleagues of Mr Dunne described him as one of the airline's up-and-coming managers. He was a close ally of former chief executive Willie Walsh.

"He would have been part of the inner circle with the last management team, so there was a little surprise when he decided to leave," said one airline source. Mr Dunne himself declined to comment last night.

Aer Lingus is currently involved in fierce competition with Ryanair, particularly on short-haul routes to Britain and Europe. Ryanair is expected to introduce significant additional capacity into Dublin in the next few months on the back of its new Boeing fleet deal.

The new chief executive of Aer Lingus, Dermot Mannion, has conceded that major growth on short-haul is unlikely for the State-owned airline in the years ahead. Instead he has stressed that future growth must come on long-haul.

It is reported that a deal with cabin crew, allowing the airline to undertake more long-haul services, may be agreed in coming weeks. Aer Lingus was forced to drop its Florida service recently because of a fall-out with cabin crew.

The airline is anxious to expand its North American service, but is restricted by a long-standing bilateral deal with the United States. The airline has warned that operating profits may take a severe hit this year because of rising oil prices and a slowdown in its cost-savings plan.