The crucial travel hub for United is still struggling to recover from air traffic control glitches that have already disrupted hundreds of flights.

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.

Staff shortages and equipment failures at Newark Liberty International Airport have raised safety concerns in recent weeks.

The airline told the Sun the e-mail was sent to passengers who have upcoming flights to or through Newark’s airport, as well as its MileagePlus

Three incidents at Newark have shaken the public. Meanwhile, the FAA is understaffed. Here's what the Trump administration wants to do about it.

During an interview with CBS News' Margaret Brennan for "Face the Nation," United Airlines CEO Scott Kirby expressed positivity about potential reform and improvement. "This is the most optimistic I've been in my entire career about finally getting the FAA fixed," Kirby said.

U.S. Department of Transportation Secretary Sean Duffy is meeting with the major airlines on Wednesday in a renewed effort to address the ongoing issues at Newark Liberty International Airport. There will not be a decision made at the end of the two-day meeting -- that will likely come at the end of the month.