The strike at British Airways has begun and the airline has been left with “no option but to cancel nearly 100% of flights.”

The strike was scheduled well in advance, and this first round will total 48 hours.

British Airways pilots are going on strike over pay, and there is “no way of predicting how many (pilots) would come to work or which aircraft they are qualified to fly,” according to the airline. The statement from British Airways, which was released on Monday, explains that the airline has “no option” but to cancel the vast majority of flights. In the meantime, the strike will carry on as scheduled, with further strikes scheduled for September 27th. British Airways, for their part, says that it offered pilots an 11.5% pay raise over three years, but the union wants more.

The airline has promised to provide affected customers with full refunds or the option to re-book. They operate over 850 flights per day and the cost of this strike has been massive. Competitive airlines have jumped on the opportunity to significantly increase the fares on tickets during the scheduled strike days. The union leader, Brian Strutton, explains that the pilots want and deserve a larger raise. “They’ve previously taken big pay cuts to help the company through hard times. Now BA is making billions of pounds of profit, its pilots have made a fair, reasonable and affordable claim for pay and benefits,” Strutton explained.