US Flight Grounding Caused by Fiber Upgrade, Officials Say

A routine upgrade to an old copper wire communications network by contractor L3Harris caused a nationwide ground stop of US flights on Friday, November 14, 2026, forcing the longest shutdown of departures since 2001.

Transportation Secretary Sean Duffy told reporters on Saturday that the work overloaded communications at 17 of the Federal Aviation Administration’s 22 en route centers. ABC News reported that the new routers started flooding other network routers with more than 1,000 connection attempts every four to five seconds.

Yahoo News Australia reported that the outage caused more cancellations than the 2024 CrowdStrike software failure, with more than 5,000 flights canceled by Saturday afternoon.

Officials ruled out a cyber-attack. US Homeland Security Secretary Markwayne Mullin said there was no evidence of foul play and sought to reassure passengers about aviation safety.

“Everybody’s safe.” “Everybody’s safe. There’s no reason to be concerned about your loved ones if they’re flying,” said Markwayne Mullin, US Homeland Security Secretary, in remarks provided to ABC/Wires.

Contractor equipment and aging infrastructure under investigation

Duffy pointed the finger squarely at government contractor L3Harris for the system overload. He said officials were investigating whether contractor incompetence or a faulty router sparked the widespread radar and communication gaps.

“Our contractor didn’t meet the moment or the equipment didn’t meet the moment,” said Sean Duffy, Transportation Secretary.

L3Harris said that it took the issue seriously and was supporting the FAA in its investigation to understand the conditions that led to the ground stop. The company noted it has completed more than 70 percent of the planned airspace communications conversion from legacy copper wires to a fiber-optic system.

The FAA spends $1 billion annually to maintain its old copper wire system. Duffy said the routers being replaced were about 25 years old and were supposed to be replaced in 2006.

Yahoo News Australia said that a previous Transportation Department inspector general review detailed an incident in 2009 where an L3Harris predecessor misconfigured a router during a fiber transition, disrupting 129 air traffic facilities.

“We need L3Harris or whoever provided that router to us to do a better job,” Transportation Secretary Sean Duffy said.

Airlines and international travelers face weekend delays

The disruption left nearly 10,000 flights canceled or delayed during the emergency. Major carriers logged thousands of cancellations, including United Airlines with 1,800 canceled flights, alongside severe impacts at Delta Air Lines and American Airlines according to flight-tracking data.

SMH.com.au reported that out of 20,000 scheduled flights remaining after the ground stop order at 3.45 pm Washington time on Friday, 12,000 had to be canceled, comprising 9,000 commercial flights and 3,000 private flights.

US airlines will not be required to compensate stranded passengers because the disruption originated in Federal Aviation Administration systems rather than carrier operations. The incident also triggered international repercussions, with European aviation authorities suspending US-bound departures and flights from Australia experiencing knock-on delays.

FAA administrator Bryan Bedford apologized to the traveling public and expressed optimism about the recovery timeline. Yahoo News Australia reported that Bedford stated schedules should return to normal by the end of Sunday.

“I do think the worst is behind us,” said Bryan Bedford, FAA Administrator, to Yahoo News Australia.