“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.

Caught in the middle of the issues at Newark is United Airlines, which is the most active airline at the New Jersey airport. While the problems lie with the FAA system, the airline is where people often aim their frustrations over cancellations and delays.

Similar to last summer, there is currently a nationwide shortage of air traffic controllers, which will “take time” to replenish, according to Transportation Secretary Sean Duffy.

United Airlines Holdings Inc. expects flight reductions at Newark airport to linger through summer and into fall as the crucial travel hub struggles to recover from air traffic control glitches that have already disrupted hundreds of flights.