Talk on how to close a huge deficit in British Airways' pension fund have adjourned without a result.
Willie Walsh, BA's chief executive, says the pension deficit threatens the airline's future
The talks - described by some union officials as "high noon" - will restart later in October.
The Transport & General Workers' Union said BA had been prepared to consider offering more cash to close the £2.1bn black hole in the fund.
BA admitted it was prepared to increase a proposed cash injection into its pension scheme as it seeks a deal.
The airline said it expected a £500m injection proposed earlier this year to increase.
However it said that would only happen if staff agree a package of measures, including raising their retirement age.
"We have indicated to the trade unions today that through negotiations with the trustees we would also expect that figure (£500m) to increase," a BA spokeswoman said.
But other unions said the airline had rejected their proposals to resolve the predicament.
For the GMB, Ed Blissett said only a "glimmer of hope" remained that the two sides could reach a deal.
The possibility of a breakdown in negotiations is just the latest problem to face BA.
Earlier this week two of its directors resigned after accusations - first aired in June - that they had been colluding with other airlines to fix fuel surcharges for long haul flights.
In March BA outlined plans to fill the deficit in its pension scheme by raising the pension age for pilots and cabin crew from 55 to 60, and for ground staff from 60 or 63 to 65.
Cabin crew would see a further increase in pension age to 65, but in five years' time.
The company also wants to cut the rate at which staff build up their pension.
The main scheme was closed to new joiners in 2003 but still has 34,000 active members.
Last month the trustees of the pension scheme revealed that a recent valuation had shown the deficit was likely to more than double to £2.1bn.
Although the trustees agreed that the company could probably not afford to make higher regular contributions, they did say that it had enough cash to make a bigger one-off injection into the fund.