British Airways owner IAG warned on Thursday full-year operating pretax profit will be 215 million euros lower than last year, as major pilot strikes grounded thousands of flights.

IAG, which reported a profit of EUR 3.49 billion (US$3.82 billion) last year, expects the strikes to hit the company by 137 million euros, with a further 33 million euro impact because of "threatened strikes" by Heathrow Airport employees.

The strikes in September backed by the pilots' union, the British Airline Pilots Association (BALPA), led to an initial cancellation of 4,521 flights over seven days.

British Airways pilots had canceled a strike set for Sept. 27 to create time for talks. BA has offered its pilots an 11.5% pay rise over three years.

"There have been no further talks between British Airways and BALPA," the company said on Thursday.

The airline, whose competition includes easyJet, Ryanair and other low-cost airlines, estimates booking trends in its low cost segments will be hurt by 45 million euros.

Shares were seen falling 5% to 7%, according to premarket indicators.