British Airways has been forced to cancel nearly all of its flights scheduled for Monday and Tuesday, due to a pilots strike. Around 195,000 customers were scheduled to fly on those two days. The strike comes as a result of stalled pay negotiations. British Airways has stated that it is ready to resume talks with the pilots union.
See "British Airways grinds to a halt as pilots go on 2-day strike", Rachel Siegel, The Washington Post, September 9, 2019