British Airways said all affected passengers were given notice of at least one or two weeks that the flight would not run.
The airline is now bringing in crew and aircraft from its Oneworld Finnair to stabilise schedules over the summer.
easyJet is also cancelling around 70 flights per day, mostly operating from its largest base, Gatwick.
Every passenger with a cancelled flight is entitled to new flights on the initial day of departure if a seat is available.
