No further talks are planned between British Airways and the Unite union on the eve of a second five-day walkout by cabin crew.
A meeting on Friday ended without agreement as the first wave of industrial action reached its fifth and final day.
Conciliation service Acas said talks had been adjourned and it was now trying to arrange further discussions.
A spokeswoman said: "We are in contact with both parties but we have no confirmation of a date for future talks."
Thousands of passengers suffered travel disruption this week as a result of the bitter, long-running dispute, with many more set for similar chaos next week.
Derek Simpson, joint general secretary of Unite, blamed the talks' failure on BA's chief executive, Willie Walsh.
The airline described Saturday as a "breather" day and said although the "vast majority" of flights were running it was impossible to run a full schedule.