Mr Brennan told the 700 people gathered at the Irish Airline Pilots Association special conference in Dublin yesterday that while the anticipated results were encouraging, it was too early to celebrate.
He urged Aer Lingus not to take the pressure off, adding he was not prepared to discuss the future investment needs of the airline until he was convinced it had survived and was in a strong position.
"At that time, we will take tough decisions about the airline and we should be able to do that in a couple of months time," he said.
There is a winter ahead before the final results are announced, he warned.
Passenger traffic at Dublin, Cork, and Shannon airports were up 11% in the first quarter of this year compared to the same period last year.
Mr Brennan also pointed out that the new Programme for Government included a commitment that as part of the transformation of Aer Rianta, the Government would ensure Shannon and Cork airports greater autonomy and independence.
He said that since the events of September 11, 2001, there had been extra security measures implemented at airports in Ireland. Access to the cockpits of aircraft had also been tightened, he said.
Despite its difficulties over the past year, the airline had adopted nine new routes and was looking at further
The minister's comments about privatisation followed calls by IALPA president Mark Tighe for such a proposal to be given the green light by the Government.
Mr Tighe said the association had no preference for the final share breakdown if privatisation occurred.
He said, however, it would not favour being swallowed up by an aircraft company, and a major share holding did not necessarily have to come from another airline.
Aer Lingus chief executive Willie Walsh said the survival plan had resulted in more than 2,000 jobs being cut, but if action had not been taken, the firm faced certain closure.
The plan had reduced costs by €190m and effectively turned around the company from a crisis situation, Mr Walsh said.