British Airways pilots have begun a 48-hour strike, grounding most of the airline’s flights and disrupting thousands of travellers’ plans in unprecedented industrial action over a pay dispute.

The British Airline Pilots Association (BALPA) last month gave the airline notice of three days of industrial action in September, in what is the first ever strike by BA pilots.

Following the strikes on Monday and Tuesday, another day of industrial action is scheduled for September 27.

BALPA has said that British Airways should share more of its profits with its pilots, but the company has said the strike action is unjustifiable as its pay offer was fair.

There is Industrial Action planned by the pilots’ union, BALPA on 9 and 10 September 2019. We apologise for the significant impact this will have on our flights. If your flight is cancelled, please don’t go to the airport. For the latest info, visit https://t.co/rPEgyOeVyh.

— British Airways (@British_Airways) September 7, 2019

Thousands of customers have had to seek alternative travel arrangements, and the airline has come in for criticism over how it handled communications with customers ahead of the strikes.

“This strike will have cost the company considerably more than the investment needed to settle this dispute,” BALPA General Secretary Brian Strutton said in a statement on the eve of the strike.

“It is time to get back to the negotiating table and put together a serious offer that will end this dispute.”

On Thursday, the airline dismissed a new offer by BALPA as an “eleventh hour inflated proposal” that was not made in good faith, but the union said it would have called off the strikes this week if BA had engaged with the offer.

A spokeswoman for Prime Minister Boris Johnson has urged both sides to end the dispute.

Asked about the strike action, a spokeswoman for British Airways said: “We remain ready and willing to return to talks with BALPA.”

-AAP