He was immediately replaced by the state-run company's chairman, Bernie Cahill, one of Ireland's best-known businessmen.
Mr Cahill's appointment was announced in a statement in the Dail, the Dublin parliament, by the Transport Minister Brian Cowen.
He said the government would be prepared to support 'convincing and visible action' by Mr Cahill to solve Aer Lingus's problems, but made it clear that a large cash injection was out of the question.
Reports yesterday indicated that the Irish airline, already facing losses running into hundreds of millions of pounds, stood to lose about pounds 90m this year alone.
Trade unions at the airline said they regretted the chief executive's sudden departure.Reuse content