Two days after a chunk of the fuselage blew out of one of the planes, the F.A.A. and the aircraft maker are still negotiating what to tell the airlines to do.

Read More Airlines and Airplanes, Aviation Accidents, Safety and Disasters, Delays (Transportation), Alaska Airlines, Boeing Company, Federal Aviation Administration, National Transportation Safety Board, United Airlines, Boeing 737 Max Groundings and Safety Concerns (2019), Regulation and Deregulation of Industry, Spirit AeroSystems Inc