The latest wave of strikes by British Airways cabin crew will end today, with further action set to be launched at the weekend in the increasingly bitter row.
Unite said the dispute had now cost the airline £112m (€133.85m) and claimed BA could lose £1.4bn (€1.67bn) as passengers switched to other carriers.
Union members will strike for the fifth day today, and plan to stage another five-day walkout from Saturday.
Unite is planning to hold another ballot of its cabin crew members, which it has to under employment law, and has warned of a summer of disruption unless there is a deal.
Talks between Unite's joint leader Tony Woodley and BA's chief executive under the auspices of the conciliation service Acas ended without agreement on Tuesday, with little sign of progress.
An agreement in principle has been struck over cost-cutting, the original cause of the dispute, but the removal of travel concessions from strikers is now blocking a deal.
Unite has urged BA to fully restore the travel concessions, arguing it would not cost the airline any money.
Cabin crew have now taken 16 days of strike action since March, with each day adding £7m (€8.36m) to the cost to BA of the dispute, according to Unite.
The union claimed BA stood to lose £1.4bn (€1.67bn) in lost sales as passengers took their custom elsewhere.
The union maintained the strike was being strongly supported by cabin crew and was having a huge impact on flights.
Strikers claimed they were being called at home by managers offering to be placed on "plum" overseas services to try to tempt them back to work.
BA plans to increase its flying schedule during the final wave of strikes by cabin crew next week because of "growing numbers" of staff wanting to work as normal, the airline said.
Derek Simpson, Unite's joint leader, told the union's national conference in Manchester yesterday that Mr Walsh was trying to "humiliate" the union, describing BA as "outrageous" employers.