The company said it is still feeling the impact from the accident.
Back in April, debris from a failed engine shattered one of the plane's windows, nearly sucking passenger Jennifer Riordan out of the plane.
Other passengers pulled her back in, but Riordan later died from her injuries at the hospital.
Southwest pulled all advertising after the incident and had said it was bracing for an impact on bookings.
Southwest's CEO said he expects the financial effects of the accident to abate in the third quarter.