Transportation Secretary Sean Duffy said the massive air traffic control outage that grounded flights across the U.S. Friday night was linked to a contractor replacing the antiquated system’s old copper wire.

Duffy gave the update at a Saturday press conference, while President Donald Trump has yet to publicly address the meltdown that left thousands of Americans stranded. Trump said “old broken stuff” was to blame in reported remarks to Fox News correspondent Peter Doocy late Friday.

The president is getting constant updates on the situation, a White House official said.

New technology being added to the nation’s air traffic control system overloaded antiquated equipment and caused “intermittent” communications and radar gaps, leading to the ground stop that lasted more than four hours, officials said at the briefing.

Duffy said a contractor had been working on replacing a section of the system’s old copper wire with new fiber wire, and that work somehow caused the system overload.

He said officials were investigating whether contractor “incompetence” or a faulty router was the cause, identifying the company as defense contractor L3Harris.

“What did L3Harris do?” Duffy asked during Saturday’s briefing, pointing out that the company owned the network as the agency’s prime contractor. “Did they make mistakes yesterday? I can’t go somewhere else.

“They own it. Or was it a faulty router? And we’re going to find that out. And frankly, we’re going to hold people accountable.”

L3Harris, which was updating communication infrastructure shortly before the outage, responded in a statement Saturday saying it is working with federal officials to determine what went wrong.

“We are supporting the FAA in its investigation to understand the conditions that led to the Nov. 13 ground stop of our nation’s air travel,” the company said. “L3Harris takes the nationwide ground stop and its impact on travelers, airlines and air traffic operations seriously.”

The U.S. air travel schedule should be back to normal by the end of Sunday, Bryan Bedford, administrator of the Federal Aviation Administration, added. He said airlines “will still have delays and cancellations” Saturday but promised that the “worst is behind us.”

Doocy relayed his conversation with the president on Friday’s The Ingraham Angle. “He said instead this seems to be a situation where there’s a bunch of old broken stuff in the infrastructure that the FAA relies on to keep planes in the sky,” Doocy said.

“He said there’s a bunch of – some of this is like 55-year-old equipment that needs to keep working, keep running, and that they have worked on it, they’ve talked to Congress about replacing, it just hasn’t gotten replaced yet. So that is the first information that we have from the president,” he added.

The president still had not posted about the ground stop as of Saturday evening, but had railed against California Gov. Gavin Newsom, in addition to a federal judge delaying his plans to overhaul a Washington, D.C. golf course.

CNN’s Kaitlan Collins noted Friday that the president was posting about reviving the entertainment industry on Truth Social as chaos was unfolding in airports across the nation. “Trump posts, not about the ground stop, but about reviving the entertainment industry in bipartisan fashion,” Collins said in a post on X.

Meanwhile, stranded passengers shared their frustrations on as ripple effects from the cancellations stretched into Saturday.

“Wow. @AmericanAir 12 hours, 3 canceled flights and not even a meal voucher,” traveler Susy Beltran posted on X. “DFW AA agents not helpful at all. So disappointed. Praying for our flight back Sunday.”

Beltran later added: “No crying. Just frustrated. We had 3 flights canceled AFTER 4.5 hours on the tarmac & 6 waiting at the airport. That’s all.”

At the Newark, N.J., airport, Umi Egchi was trying to figure out when his flights would line up so he could return home to Japan.

“I’m not sure exactly what happened. I just want to go home,” said Egchi, who had a sleep mask on top of his head.

Democrats called for a closer examination of the communications failure and the outdated technology underpinning the nation’s air traffic control system.

Rep. Ted Lieu, a California Democrat, called the FAA’s communications failure completely unacceptable, telling the Los Angeles Times: “I urge the FAA and the Trump administration to make sure this never happens again.”

Lieu also called for congressional hearings to determine what caused the breakdown and what needs to be done to prevent another nationwide disruption.

“What just happened is enormously damaging to trust in our air system, and our air system is a vital component of our national economy,” he said.

Sen. Tammy Duckworth, an Illinois Democrat and ranking member of the Senate Aviation, Space and Innovation Subcommittee, also called for a full investigation into the outage.

“The safety of our skies is built on redundancies,” she said in a statement. “Whatever led to the nationwide ground stop will warrant a thorough and complete investigation.”

Pete Buttigieg was in disbelief after watching Friday’s joint press conference with Duffy and Homeland Security Secretary Markwayne Mullin, according to The New York Times.

“You can just write down the comic book asterisk swearing characters,” he told the newspaper. “I have questions.”

The FAA ordered the hours-long nationwide ground stop Friday after a communications failure disrupted 22 regional air traffic control centers. The order temporarily halted departing flights while allowing planes already in the air to land, triggering widespread delays as officials worked to restore normal operations.

With reporting from agencies