MILWAUKEE (CBS 58) — A nationwide ground stop that halted departures across the United States for more than four hours Friday left travelers scrambling to change plans at Milwaukee Mitchell International Airport and airports across the country.

The Federal Aviation Administration issued the ground stop shortly before 3 p.m. Central time Friday, Nov. 13, after a telecommunications outage affected regional air traffic control centers nationwide.

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Flights already in the air were allowed to continue to their destinations, but departing flights were held on the ground as a safety precaution.

The FAA lifted the nationwide stop Friday evening, allowing departures to resume. Airlines warned, however, that the ripple effects from thousands of delays and cancellations could continue into the weekend as planes and flight crews were left out of position.

At Milwaukee Mitchell, travelers were trying to figure out what was happening while also making backup plans to reach their destinations.

Michael Esiobu and Patrick Johnson were already aboard their flight to Phoenix when they learned they would not be leaving as scheduled.

"We were actually on the plane to get ready to go and then we got the announcement," Johnson said.

Esiobu and Johnson, popular podcasters traveling to the final stop of their tour, said about 300 people were expecting them Saturday. The delays left them unsure whether the show would go on as planned.

"Captain just said that it will be an hour delay," Johnson said. "The hour delay turned into two hours. Then it turned into seven hours. Now we're here."

They were among travelers across Milwaukee dealing with the effects of the rare nationwide shutdown.

Jim Martin was trying to return home to Oregon.

"Something's going on and nobody really knows," Martin said. "I heard, like everybody else, that flights are grounded, and I looked at the board and everything is delayed."

Federal officials said the disruption involved communications between air traffic control facilities. Homeland Security Secretary Markwayne Mullin said Friday there was no indication the outage was caused by a cyberattack or other attack on the country.

The ground stop was the first nationwide grounding of U.S. departures since an FAA computer outage in January 2023.

George, who was trying to fly to Washington, D.C., for a wedding, said he first learned about the situation while arriving at the airport.

"I was getting into the parking lot and I heard it on NPR," he said.

As delays mounted, travelers began looking for other ways to reach their destinations.

James Newton of San Diego said a friend called him from a hotel with the news.

"A friend called from the hotel where we did the workshop and said, 'Guess what, it's shut down. The whole country is shut down,'" Newton said.

Esiobu and Johnson rebooked a flight out of Chicago and planned to drive to O'Hare International Airport in hopes of keeping their tour schedule intact.

"They were saying that they don't know how long it's going to take, to be honest," Esiobu said. "It could be till tomorrow morning. That could be no flights going out as well tomorrow."

Other travelers headed to rental car counters.

"I want to at least have a car locked up, so I'm not spending the night in the airport," Martin said. "I'll go visit family in Indianapolis."

CBS 58 also spoke with a couple who rented a car and planned to drive about 15 hours to Oklahoma City.

Others turned their attention to finding somewhere to stay.

"My plan is to get a hotel room and go spend the night," Newton said. "And then find out tomorrow what's happening."

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Another group told CBS 58 they were able to book hotel rooms through Sunday.

Even after departures resumed Friday evening, airlines cautioned travelers to expect continued disruptions as the aviation system worked through the nationwide backlog.