“I equate a good, A-level, traffic controller that can handle a place like Newark, JFK, LAX, San Francisco, to a three dimensional chess player who can juggle a chainsaw, an axe, a sword, a razor blade with his eyes closed,” Aero Consulting Experts CEO and a former United pilot Ross Aimer told Fortune.

The agency plans a multibillion-dollar upgrade effort, including new fiber-optic data lines between New York and Philly.

According to a new report from CNN, air traffic controllers "repeatedly" warned of major safety issues and technology outages as early as last summer, months before the April 28 outage that has been a major factor in the widespread delays and cancellations at the second-busiest airport in the New York City area.