The strike was called for by the British Airline Pilots Association (BALPA) amid a heated dispute over pay with the airline.
BALPA
said Sunday on Twitter that it submitted a proposal to the carrier's management on Wednesday, but had not yet received a response.
British Airways said in a statement released Monday that it is still "ready and willing to return to talks with BALPA."
The airline said it was forced to cancel so many flights because "without details from BALPA that pilots would strike, we had no way of predicting how many would come to work or what aircraft they are qualified to fly."
Customers who had flights booked for Monday and Tuesday will probably "not be able to travel as planned," British Airways said. The airline also advised customers not to go to the airport.
Members of the pilot union voted 93% for a strike in July. BALPA said last week it would be willing to reject it if British Airways returned to the negotiating table.
According to the site, BALPA represents more than 1[ads1]0,000 pilots in the UK – more than 85% of all commercial pilots flying there.
The Pilot Federation also intends to strike on September 27. British Airways said Monday it will be in touch "over the next few weeks" to let customers traveling on or around that date know if they are affected.
While the union is calling for higher wages, British Airways has said its 11.5% increase over three years "fairly" and above the UK's current inflation rate. In a statement released last month, it said the strike could "destroy the travel plans of tens of thousands of our customers." The strike called "a reckless course of action."