Thousands of US flights remained cancelled or delayed two days after a nationwide ground stop froze air travel, leaving passengers stranded as investigators probed a faulty computer router installed during telecommunication upgrades.
The Federal Aviation Administration lifted its nationwide ground stop after about four and a half hours on Friday, but schedule disruptions persisted through the weekend, according to BBC News. On Saturday, airlines cancelled more than 5,900 flights while over 7,000 others suffered delays.
UPDATE: We spoke with the CEO of L3Harris, and the contractor secured the two routers from the remote FAA facilities in Texas and Arkansas. L3Harris is now conducting deep diagnostics testing at their headquarters in Florida. @FAANews, Juniper, and Cisco engineers are assisting… pic.twitter.com/pdzx6qVZSf
Investigators are still working to determine the root cause and assign responsibility for the shutdown, though US Transportation Secretary Sean Duffy explained that the administration ordered the ground stop after failures in a key system allowing air traffic controllers and pilots to communicate, BBC News reported.
Duffy said that a computer router installed as part of an upgrade from copper wire to fibre optic cables started sending out faulty signals. Speaking on Sunday, he added that the router—a piece of equipment directing traffic across the network—was installed in El Dorado, Arkansas, and flooded the network.
The maintenance involved replacing telecommunication lines from old copper wire to fiber optic cables, a process that has occurred thousands of times without issues, Duffy told CNN, according to The Guardian. The contractor, L3Harris, is conducting diagnostics testing, and Duffy noted there remains no indication of a foreign cyberattack.
The FAA has issued a nationwide ground stop for all flights. Travelers should confirm their flight status with their airline before heading to the airport.
By contrast, the nationwide travel chaos triggered a political clash over funding and responsibility. Duffy blamed prior presidents and Congress for a lack of infrastructure funding, telling CNN that the $12.5bn provided by lawmakers was limited in scope.
“I have no money in that $12.5bn that I can use for a new architecture for telecom,” Duffy said. Democratic Senator Chris Van Hollen of Maryland disputed that assertion, telling CNN that Congress has given the administration what it requested for improvements.
President Donald Trump weighed in on the situation on Sunday via social media, urging lawmakers to allocate money for a comprehensive overhaul. “It will be the BEST SYSTEM anywhere in the World. Much of our current air control system is 50 years old – RIDICULOUS! We have already started the work, but it should be done all at once, not in drips and drabs,” Trump said on Truth Social.
Aviation experts echoed concerns regarding the state of the infrastructure. Aviation analyst Miles O’Brien described the US system to BBC News as a house about to be condemned, noting that the aviation network has been allowed to decay beyond a fixer-upper.
In September 2026, a US government report classified 51 of the FAA’s 138 air traffic control systems as unsustainable, and another 54 as potentially unsustainable, according to The Conversation. A similar nationwide ground stop occurred in January 2023 due to a malfunction of the FAA’s Notice to Air Missions system.
“With a brand new state of the art system, we wouldn't have these outages… At 8:15 tonight, eastern time, we've opened up the air space…" Secretary Mullin & Secretary Duffy provide an update on the FAA National Ground Stop. pic.twitter.com/twTyQ9UJQ0”
| Metric | Detail |
|---|---|
| Saturday Cancellations | More than 5,900 flights |
| Saturday Delays | More than 7,000 flights |
| Unsustainable FAA Systems | 51 out of 138 systems |
During Friday’s ground stop, commercial aircraft remained airborne while flight crews navigated the situation with minimal information. John Cox, a former commercial airline pilot and aviation safety expert, described the initial pilot response when speaking to NPR.
“I think the first thing would be, let’s try to find out what we can do to stay in communication. There are backup frequencies. There are other pilots that we can talk to,” said John Cox, aviation safety expert.
Duffy warned that issues will continue to arise until the United States makes major modernizing changes to its air control system. “Let’s not lie to each other,” Duffy said on NBC’s Meet The Press. “We have to make investments into a network that has been neglected for decades.”
Secretary Mullin and Secretary Duffy Brief Members of the Press on the FAA Ground Stop https://t.co/uyvQ5bVOvb
Earlier coverage: FAA Router Upgrade Triggers Nationwide Ground Stop and Flight Delays
More on John Cox
The nationwide FAA ground stop has been lifted. Flight delays and cancellations continue. Check with your airline for the latest information.
