Ryanair's chief executive, Mr Michael O'Leary, has no plans to apologise for stating that the best way to settle the budget airline's differences with Aer Rianta was "with Semtex" during a board meeting, his spokeswoman said last night.

Mr O'Leary's comments, reported in the Wall Street Journal, prompted an Aer Rianta worker-director to claim he was unfit to have the care of airline customers entrusted to him.

The comments were "malevolent and shocking", Ms Rita Bergin said. Stating that Mr O'Leary proposed to "resolve business differences in a manner which is far too fresh in the minds of people on the island of Ireland", she said this smacked of an intemperate, arrogant and aggressive attitude.

Mr O'Leary's spokeswoman said he did not regret the comments. She said "no" when asked whether Mr O'Leary feared they might damage his interests.

Ms Bergin said: "Here we have an individual worth well in excess of £100 million behaving in a shockingly irresponsible manner. It begs one question: are we interpret the silence of his board of directors as condoning his comments?"

Ms Bergin's comments followed those of a worker-director colleague on Aer Rianta's board, Mr Peter Dunne, who spoke against Mr O'Leary on RTE radio.

Aer Rianta has declined to comment on the matter, but it is thought that staff and other board members are unhappy about the language used by Mr O'Leary.

Mr O'Leary has been involved in a long-standing dispute with Aer Rianta over landing fees.