British Airways customers are still facing the prospect of disruption to summer holidays after the airline failed in a legal bid to block strikes by pilots.

Speaking after the Court of Appeal dismissed BA’s challenge to the legality of the ballot, the Balpa union said it would not announce strike dates yet to allow further talks at the conciliation service, ACAS. But it warned the airline it would have to make concessions in its approach to the long-running pay row by the end of the week.

By law, the union has to give 14 days’ notice of any strike dates before any action could hit services. It means that any holidays completed within the next fortnight, at least, will be safe from any disruption.

BA went to court last week after pilots voted 93% in favour of strikes. The union has been in talks since last November over a new three-year pay deal. It wants a profit share and share save scheme too.

BA has offered an 11.5% increase over the term – in line with rises offered to other workers.

Balpa general secretary, Brian Strutton, said: “BA’s attempt to defeat the democratic view of their pilots in court, rather than deal with us across the negotiating table, has sadly wasted huge amounts of time and money that could have been put into finding a peaceful resolution.

“Now the window for negotiation and compromise is closing fast. BA need to wake up to reality.”

He added: “BALPA wants to resolve this matter through negotiation and so we are not announcing strike dates. Instead, we have called on BA to hold further talks at ACAS and they have agreed to meet at ACAS today and for the rest of this week for one last try to resolve this dispute by negotiation. We have spent four days in talks at ACAS already, and BA refused to move their position one iota.”

The airline’s barrister told the High Court last week that the proposed action is designed to cause “the maximum in disruption” and could cost the airline up to £40m a day.

The airline’s statement said it was “sorry” for the distress caused to customers by the threat of strikes. It read: “While no strike dates have yet been issued by Balpa, and they are required to give us 14 days’ notice of any intention to call strike action, we ask our customers to review their contact details by visiting ba.com, or by contacting their travel agent.

“We continue to pursue every avenue to find a solution to avoid industrial action and protect our customers’ travel plans.

“Our proposed pay deal of 11.5% over three years is fair, and by contrast to Balpa, has been accepted by the members of the Unite and GMB trade unions, which represent nearly 90% of all British Airways colleagues.”