The action at British Airways would come at the tail end of the peak season for European travel, threatening earnings at parent IAG SA. The UK unit's lucrative long-haul routes helped lift the group's second-quarter operating profit 18 per cent, the best performance among leading European carriers.
BA, which has about 4,000 pilots at London Heathrow and 300 at Gatwick, said it will make changes to its schedule to operate as many flights as possible, while Spanish sister carriers Iberia and Vueling, together with Ireland's Aer Lingus, could help provide additional capacity.
All the same, some flights will have to be canceled and the company will begin to inform customers in a matter of hours, Chief Executive Officer Alex Cruz said on a media call. People unable to fly will be able to rebook or get a refund.
"It is completely unacceptable that Balpa is destroying the travel plans of tens of thousands of our customers with this unjustifiable strike action," BA said, adding that it has offered a pay deal worth 11.5 per cent over three years that will take basic salaries to about 200,000 pounds.
The labor conflict comes with BA also facing pressure from a possible no-deal Brexit, which could further weaker pound against foreign currencies and cause Britons to curb spending on overseas travel. The carrier last month sought to block a strike by seeking a legal injunction, but failed in the bid.
Balpa said that the ballot results are valid until January and more strike dates may be announced.