FAA lifts nationwide ground stop that disrupted thousands of flights; White House says no indication of "nefarious act"

Federal airspace is operating normally after a nationwide ground stop on all departing U.S. flights threw the aviation industry into turmoil Friday. Officials said the issue stemmed from a "telecommunication outage." 

The FAA had issued the ground stop on all departing flights due to "extraordinary circumstances and for reasons of safety." The ground stop lasted about five hours. 

As of 7:30 a.m. ET on Saturday, the airspace was operating as normal and being closely tracked, senior government sources familiar with the situation told CBS News.

"Operations are slowly returning to normal this morning. Planes are pushing back, taxiing, and taking off, and it is safe to fly," Transportation Secretary Sean Duffy said in a social media post on Saturday. "We are in close coordination with the airlines to support the ongoing recovery."

He warned that travelers will continue to see some delays and cancellations as carriers reschedule flights and reposition crews.

"Our top priority right now is making sure travelers get home safely to their families as quickly as possible," he said. "To our air traffic controllers, pilots, and flight crews who are working around the clock: the nation thanks you for your professionalism and dedication to the flying public."

There are more than 2,000 delays and more than 3,800 cancellations in the U.S. on Saturday, according to the flight tracking website FlightAware.

Delta Air Lines led the way with 640 cancellations, while United had 530 and American had 488. Atlanta's Hartsfield-Jackson International Airport, Chicago O'Hare International Airport and New York's John F. Kennedy International Airport were most affected by the cancellations on Saturday morning. There were also about 1,400 flights delayed. 

Preliminary investigation indicates routers caused outage 

Duffy said Friday that routers became overloaded with data and began to provide inconsistent information. 

"Because of that, we shut the system down," Duffy said, noting the air traffic control system is "incredibly old." 

Homeland Security Secretary Markwayne Mullin said in Friday's briefing that new security patches introduced into the older system appeared to "overwhelm" its routers.

The FAA's preliminary investigation has led the agency to believe the issue was limited to Cisco 600 series routers that were manufactured between 2001 and 2006, senior government sources told CBS News. The sources said the faulty equipment has been identified and isolated. 

The sources said the routers essentially got overwhelmed and started feeding out-of-sync data packets into the larger air traffic control system. That causes static over voice communication lines and can cause screens to flash or go to black. 

Sources told CBS News they are receiving conflicting information about the cause of the issue. Multiple sources said Friday that an update to the private communications network that connects the U.S. air traffic control system caused the system to reboot, leading to a crash and a communications outage.

Officials call for emergency funding to modernize ATC  

The FAA Telecommunications Infrastructure, known as FTI, is the communications backbone that connects air traffic control centers and other FAA facilities. It supports the transmission of essential voice communications and operational data used to manage air traffic. The system is operated by L3Harris, which did not immediately respond to CBS News' request for comment. 

The FAA awarded Harris Corp., the predecessor to L3Harris, a contract to modernize, operate and manage the network in July 2002.

A November 2023 FAA-commissioned safety review described the FTI network as obsolete and said it depended on an older communications technology known as TDM.

The review also warned that the technology was no longer supported by the telecommunications infrastructure on which it relied and that an unexpected failure could leave individual FAA facilities, or even an entire regional air traffic control center, disconnected from the broader network.

There has been frustration with L3Harris's communication and response, sources told CBS News. 

On Friday night, Duffy renewed his call for Congress to approve emergency funding to modernize the nation's air traffic control system.

"But you will have more of these," Duffy said during the news conference. "You will have more of them unless the American people and the Congress tell us to build." 

Mullin argued that the incident demonstrated why he believed piecemeal modernization was insufficient and said the Trump administration wants a complete replacement of the air traffic control system, at an estimated cost of $50 billion.

"No indication" of cyber attack or threat, Mullin says

Mullin told reporters in an earlier briefing outside the White House Friday that "there was no indication, as of yet, that this was a nefarious act against us. It was just a telecommunication outage, as of right now." 

"There is no indication, we had no reason to believe, that as of right now, that this was a threat to the United States," Mullin said. "This was a telecommunication outage throughout FAA. Out of an abundance of caution, we have grounded all the flights. And all the flights are accounted for."

Mullin reiterated Friday night that there was no cyberattack and the ground stop was not related to the massive global Microsoft outage.

"I want to make sure everybody understands that there is no connection between this and Microsoft," Mullin said during the news briefing with Duffy. "I know a lot of people are making that jump. This is so far what we've seen. There is actually no cyberattack. We're still working through that process."

Chaos for travelers  

According to the flight tracking site Flightradar24, there were about 3,100 airborne aircraft bound for U.S. airports when the ground stop began. Planes were able to land safely, Mullin said, but with no aircraft able to take off again, delays began piling up at major airports across the country in Boston, Atlanta, Miami, Pittsburgh, New York City, Los Angeles and Baltimore. 

"This is absolutely unprecedented," said Robert Sumwalt, a former chair of the National Transportation Safety Board and a CBS News transportation safety expert. "I was an airline pilot for 24 years. I was in the air on 9/11. That was the last major ground stop. There was one back in 2023 for just a few hours. This is absolutely unbelievable that this could happen in this day and age."  

Overall, 9,159 flights were cancelled and 7,190 were delayed on Friday, according to FlightAware. It was the second-worst travel day for airlines this year: A massive snowstorm on Jan. 25, 2026 led to 11,607 flight cancellations. 

In January 2023, a nationwide ground stop was ordered for a few hours, and domestic flights were delayed nationwide due to an FAA system outage. The FAA said at the time that its flight personnel alert system went down overnight.