Air France-KLM (AIRF.PA) has put the total cost of last month’s two-week pilots strike at 500 million euros ($632 million), enough to wipe more than a fifth off the group’s estimated full-year core profit and sending its shares to a 13-month low. The Franco-Dutch group said on Wednesday total passenger traffic fell 15.9 percent in September compared with the year before, adding that bookings for the fourth quarter were down by between 1 and 2 percentage points.