The incidents were extreme examples, but they fit into a pattern that reveals glaring vulnerabilities in one of the most important protective layers of the nation's vaunted aviation safety system.
In the past two years, air traffic controllers and others have submitted hundreds of complaints to a Federal Aviation Administration hotline describing issues like dangerous staffing shortages, mental health problems and deteriorating buildings, some infested by bugs and black mold.
There were at least seven reports of controllers sleeping when they were on duty and five about employees working while under the influence of alcohol or drugs. The New York Times obtained summaries of the complaints through an open-records request.
Air traffic controllers, who spend hours a day glued to monitors or scanning the skies with the lives of thousands of passengers at stake, are a last line of defense against crashes. The job comes with high stakes and intense pressure, even in the best of conditions.