BA was forced to cancel the “vast majority” of its flights on Monday and Tuesday (9-10 September) due to the strike, and warned the knock-on effect would linger for the rest of the week.

The flag carrier said it operated around 90% of flights on Wednesday, despite displacement of around half its fleet, more than 700 pilots and some 4,000 members of cabin crew.

Balpa has a further 24-hour walkout scheduled for 27 September, and has not ruled out calling further strike action amid its dispute with BA over pay and conditions.

“Should British Airways refuse meaningful negotiations, further strike dates will be considered by the Balpa national executive team,” the union has warned.

In a statement, BA said: “Further industrial action by Balpa, the pilots union, is planned for Friday 27 September. We remain ready and willing to return to talks with them.

“As a result, we are reviewing our flying schedule and we will offer affected customers the option to receive a full refund or the option to rebook to another travel date or on an alternative airline."

Balpa has been in dispute with BA for several months over pay and conditions. Balpa says BA is failing to adequately reward its pilots for helping deliver record profits for BA and owner IAG last year.

BA has previously accused Balpa of refusing to agree to talks without pre-conditions, while Balpa says BA has repeatedly refused to reconvene at government conciliation service Acas.