The report follows two fatal Boeing aircraft crashes, killing nearly 350 people, and the recent incident where a doorplug blew out midflight, resulting in the grounding of Boeing's 737 Max fleet.
The NTSB indicates the missing bolts were removed during a repair procedure in September, and never replaced.
Cellphones, headrests and even a boy's shirt were ripped out of the plane when a door plug suddenly failed, traumatizing passengers both physically and mentally, according to a class action lawsuit against Boeing.
Concerns about the safety of Boeing 737 Max 9 planes emerged after a door plug blew out of an Alaska Airlines flight on Friday, forcing the plane to make an emergency landing.
The alert stems from several major safety violations as demand for air travel increases amid a spate of industry-wide retirements.
Nearly 400,000 children in the U.S. live near airports and may be exposed to lead air pollution from small planes, the agency found
