Southwest Airlines Co. projects a drop in bookings this quarter as federal investigators examine a mid-air engine failure that led to the death of a passenger.

Jennifer Riordan, a Wells Fargo executive from Albuquerque, was killed when shrapnel from the power plant pierced the cabin of the Boeing 737 airliner en route to Dallas from New York City. Advisers from both Boeing and the engine-maker, CFM International, are assisting authorities.