Duffy Says an L3Harris Crew Was Working on the FAA Network When Flights Stopped. Its Stock Fell 4% After Hours

A retired couple in their late 60s with a $1,200 round trip to see their grandchildren were among the travelers stuck at the airport Friday night. Their airline owes them nothing for the hotel.

Because the FAA caused the delays, airlines are not required to compensate stranded passengers, Reuters reported. On Saturday, Transportation Secretary Sean Duffy named the company whose crew was working on the air traffic control network when the nation’s flights stopped: L3Harris Technologies (NYSE: LHX).

Here is what happened, what you can still get back, and what it means for L3Harris owners.

Copper wire, fiber and one router

Duffy said an L3Harris contractor crew was at “at least one” remote FAA site Friday afternoon, switching telecommunication lines “from old copper wire, and they’re bringing it over to fiber.” Politico reported that the fiber work has been going on for months across dozens of facilities.

Duffy said a router “started flooding other routers in our air traffic control system,” with “over 1,000 connection attempts every four to five seconds.” He said the trouble began at 3:36 p.m. ET, when air traffic control centers saw instability in radar and communications.

“Our switches, our routers actually got overloaded with data and they started to give us inconsistencies in the data from those routers and because of that we shut the system down,” Duffy said Friday night, according to Reuters.

The FAA ordered a nationwide ground stop that lasted almost five hours, Reuters reported. It was the longest nationwide halt of flights since the September 11, 2001, attacks. Once crews isolated the work at the remote site, Duffy said, “all of our systems came back online.”

Duffy said officials do not yet know whether the L3Harris crew made a mistake or the router itself was faulty. “What we’re working to determine is did we have incompetence, meaning was it user error, from L3 Harris? Or, did they install a faulty router?” he said, according to Politico. L3Harris did not respond to requests for comment from Reuters, Politico, Barron’s or Yahoo News.

Officials ruled out the two theories that spread fastest on Friday night. “We don’t believe this was cyber at all,” Duffy said. FAA Administrator Bryan Bedford said there was “zero evidence of anything nefarious and zero evidence of anything AI related.”

What travelers can still get back

FlightAware counted more than 9,100 canceled flights within, into or out of the U.S. on Friday, Yahoo News reported. American canceled 1,239, Southwest 1,167, Delta 1,162 and United 1,137. Reuters counted more than 3,700 more U.S. cancellations and 2,000 delays on Saturday, and Bedford said he expects 4,000 to 5,000 of about 41,000 scheduled flights to be canceled.

The airlines have opened free rebooking, each with its own rules, Yahoo News reported:

• Delta waived fare differences for travel Nov. 13 to 15 if you rebook by Nov. 22.
• United waived change fees and fare differences for Nov. 13 and 14 trips rebooked through Nov. 20.
• Southwest offers no-cost rebooking or standby for Nov. 13 to 16 travel.
• American waived change fees at 21 airports for Nov. 13 and 14 trips, with changes booked by Saturday.

For the couple with the $1,200 trip, free rebooking saves the cost of new tickets. The hotel and meals from Friday night stay on their own card, because the delay was the FAA’s doing.

What it means for L3Harris owners

L3Harris shares closed Friday at $272.35 and fell to $261.00 in after-hours trading, down 4.2%. A 67-year-old with 500 shares had about $136,000 in the stock at the close and about $130,500 after hours, a drop of about $5,700 before Monday’s open.

This is the second time a fiber move on this network has gone wrong. In 2009, a technician for Harris Corp., the company that later merged into L3Harris, misconfigured a router during a fiber move and disrupted 129 FAA facilities, according to a Department of Transportation inspector general review cited by Yahoo News.

“L3Harris actually owns that network,” Duffy said. “Until I can build” a new one, “I’m stuck with L3Harris.” The FAA picked AT&T in August to lead a replacement network, Yahoo News reported, and Duffy now wants Congress to approve $50 billion to rebuild air traffic control, up from the $30 billion he sought earlier. “This is an emergency,” he said.

The stock closed Friday down 7.2% for 2026 and on pace for its worst year since 2011, Barron’s reported, citing Dow Jones Market Data. Airline stocks fell after hours too: Delta 2.4%, United 1.9%, American 1.8% and Southwest 1.3%.

What to watch

The fault finding decides the rest. If the router was defective, L3Harris installed bad equipment on a network the FAA was already replacing. If it was user error, Duffy’s word “incompetence” stays attached to a company that lives on government contracts.

If you are traveling this week, rebook through your airline’s own page before the waiver dates run out, and keep your hotel and meal receipts. If you own L3Harris for its defense business, one bad Friday on an FAA network that was already being replaced changes little. If you own it because you trust management with its government contracts, Saturday’s press conference gave you a reason to look again before Monday’s open.

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