AHMEDABAD, India—Investigators probing the deadly crash of an Air India Boeing 787 have recovered the aircraft’s flight recorders, a key step in determining the cause of a tragedy that killed more than 260 people. The London-bound aircraft crashed shortly after taking off with 242 people on board on Thursday, leaving a single survivor. A total of 265 people were confirmed dead as of Friday, including medical students at a hostel and other victims in the residential neighborhood where the plane went down, Ahmedabad police said.