The Government has not ruled out a management buyout of Aer Lingus, the Minister for Transport, Mr Brennan confirmed today.
He said ministers would make a decision on the future of the highly-successful company in early autumn.
"You can't rule it out. If the government decides to take outside investment in the airline and recommend that to the Dail, if we go that road, and that is an if, we then have to decide how to do it," Mr Brennan said.
He said the vast majority of airlines were losing money and any decision must be made with care.
"We have been through three or four crises in Aer Lingus and on each occasion we have invested funds and restructured, and there has been a lot of pain for everybody involved.
"One question we must look at is whether we want to go back into that cycle again."
The Government-sponsored bill for the break-up of Aer Rianta got the necessary go-ahead from both houses of the Oireachtas this week.
Mr Brennan defended the legislation - insisting it was not rushed and there were no flaws in it.
He said he was surprised at the severity of the attack from Fianna Fail's Ms Mary O'Rourke, leader of the Seanad, launched over the Aer Rianta proposals this week.
"I thought it was very trenchant and but then she must feel very deeply about it," he told RTE Radio.
"Individual members no matter how senior are entitled to express their opposition and their individual concerns and that is what Mary O'Rourke has been doing," he said.
Mrs O'Rourke said the Airports Bill, which provides for creating three separate companies to run Dublin, Cork and Shannon airports, was flawed and being rushed through the legislative process.