Mr Cahill devoted most of his working life to the dairy industry but it was as chairman of Aer Lingus that he recorded his most marked success in business.
Aged 61 when he joined the State-owned airline in 1991, he also served as chairman of Irish Sugar, now Greencore, and led a food company sold for £100 million in 1992.
Aer Lingus group chief executive Mr John O'Donovan last night said Mr Cahill had contributed immeasurably to the airline.
"Aer Lingus was privileged to have Bernie Cahill at the helm for over 10 years. His unparalleled business acumen successfully guided Aer Lingus through the 1990s, recording record results through some of the most difficult times in the company's history.
His untimely death will leave a major void in Irish business." Mr Cahill was best known as architect of the rescue plan which saw Aer Lingus return to profitability in the late 1990s from the brink of insolvency earlier that decade.
A financial crisis provoked by a downturn in the global aviation business after the Gulf War had put the airline's very survival in doubt.
The rescue plan developed with the company's management and trade unions saw significant State resources injected into the troubled company and major restructuring.
To ensure its viability, staff agreed to a pay freeze.
During the recovery process, the company's aircraft maintenance business, TEAM Aer Lingus, was sold to a Danish conglomerate, FLS Industries.
As the airline returned to profit, it entered discussions which led it to join the OneWorld alliance of airlines, with companies such as British Airways and American Airlines among its members.
The link with OneWorld paved the way for the Government to allow the Aer Lingus board prepare the company for a Stock Exchange flotation.
Work proceeded on that plan until earlier this year when it became clear that the company's difficult industrial relations and market sentiment internationally would make a flotation very difficult.
Ironically, it was the very pay restraint agreed during the rescue plan which provoked strikes over conditions in the past year.
The company subsequently reached agreement with most of its workers.
A trade sale of the airline has been mooted by Mrs O'Rourke, but no formal decision has been taken by the Government to abandon the flotation.
Born in 1930, Mr Cahill grew up in Bere Island, Co Cork. He was educated at University College Cork and worked first for the Condensed Milk Company of Ireland. He joined Express Dairies in Britain in 1957.
He returned from Britain in the 1960s to establish a business for Express in the Republic. The company was worth £100 million when sold in 1992 by its parent, Grand Metropolitan, to Waterford Foods and a group of Cork co-operatives.
Mr Cahill was made chairman of the Irish Sugar Company in 1985 by the Fine Gael/ Labour coalition.
In 1991, the company was floated as Greencore on the Stock Exchange. He remained chairman at Greencore until earlier this year.
Mr Cahill also served as chairman of Feltrim Mining, the quoted exploration company run by Mr Conor Haughey, son of Mr Charles Haughey, the former Taoiseach.
