Talks aimed at resolving the dispute which left thousands of British Airways passengers stranded have made "little progress", a senior union source says.
About 200 stranded passengers are still waiting to fly
The Transport and General Workers' Union (T&G) is locked in talks with Gate Gourmet, the in-flight catering company which sacked 670 of its staff.
The union wants them all reinstated but the firm will only accept half of them back. Talks will resume at 0930 BST.
Some 200 passengers are still waiting for flights after last week's dispute.
The dismissal of the Gate Gourmet workers led to a sympathy strike by BA baggage handlers.
Many flights were disrupted, bringing chaos to 70,000 Heathrow passengers from Thursday to Sunday.
T&G general secretary Tony Woodley dismissed the catering firm's offer to reinstate half the sacked staff, saying it was "not acceptable".
Gate Gourmet has maintained that it has to change "outdated working practices" and cut costs at its UK operations in the face of huge losses.
The BBC's industrial correspondent Stephen Cape said a senior union source had told him little progress had been made, but both sides were committed to further negotiations.
Our correspondent added: "All sides realise the full implications of failure in these talks."
Loss of revenue
Some 200 people stranded by the strike were still waiting at hotels near Heathrow on Monday night.
BA said all 200 passengers now had confirmed bookings on flights scheduled to depart by Thursday.
Meanwhile, baggage handlers have been working to return about 5,000 pieces of luggage which had become "stuck in the system" to their owners.
The cost of the strikes to BA in loss of revenues, refunds and the expense of accommodating passengers in hotels is estimated at up to £40m by airline industry analysts.