MIDDLETOWN, Pa. (WHTM) — Planes are flying again after a nationwide ground stop on flights across the U.S. this morning. That grounding lasted hours and led to delays and cancellations at airports from coast to coast, including at Harrisburg International Airport.

The FAA says there was a massive computer failure with its Notice to Air Missions system, which delivers key safety warnings for pilots.

No flights were able to take off during that ground stop, which ended around 9 a.m. on Wednesday and caused a ripple effect at airports including HIA. For example, a flight scheduled for departure from the Midstate airport at 11:45 was pushed back to 12:47.

abc27 spoke to a couple hoping to get to Orlando and another woman traveling to Denver, but first, they have to catch their connecting flight.

“You always try to prepare yourself. It’s like, hope for the best but not be surprised when something like this happens, although something this magnitude — who knows what Newark is going to be like, I can’t imagine,” said one traveler.

“I am flying for a business and so I have an event tonight in Denver, so I’m hoping to not miss it,” said another traveler.

“Airlines have a lot of figuring out to do, what airplanes are available, what crews are available, what city are they in, how can we get them back on a normal system? So that’s going to take some time, so if you’re traveling today or even tomorrow morning, know your flight status before coming to the airport,” advised Scott Miller, spokesperson for HIA.

The White House says the president was briefed, and there is no evidence this was a cyberattack at this point. The Department of Transportation will investigate.

HIA is a smaller airport. Airports like Atlanta, Charlotte, and LaGuardia had to issue their own ground stops because of the backlog.