Democrats press Trump administration for answers as nationwide ground stop grips U.S. air travel

WASHINGTON — Democrats are demanding answers about Friday’s temporary ground stop on all flights in the United States and the alarming communications issue that affected air traffic control centers.

The hours-long ground stop crippled air travel and raised myriad questions about the nation’s aging air traffic control systems.

The problem stemmed from a data overload on the 1980s-era copper-wire technology used to transmit air traffic control voice and radar data, Transportation Secretary Sean Duffy said at a Friday evening news conference. This caused inconsistent communications between airplanes and controllers, prompting the Federal Aviation Administration to stop flights from taking off until the system was safely brought back online.

For several hours, both the public and members of Congress were left in the dark about the cause of the crisis.

In an interview shortly after the ground stop was announced, Rep. Ted Lieu (D-Torrance) said the FAA telecommunications outage was completely unacceptable and that the agency needs to create systems that do not have a single point of failure.

“I urge the FAA and the Trump administration to make sure this never happens again,” he said.

The California congressman said there need to be congressional hearings on the cause of the technical issue and what improvements should be enacted to avoid similar future outages.

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

Sen. Tammy Duckworth (D-Ill.), the ranking Democrat on the Aviation, Space and Innovation Subcommittee, said she will be demanding answers from the FAA about the ground stop.

“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.”

Duffy said President Trump has been pushing hard to modernize the FAA’s infrastructure and secured $12.5 billion through his 2025 “Big Beautiful Bill” — a sprawling collection of tax breaks, spending cuts and other Republican priorities — to upgrade the nation’s air traffic control and airspace systems. Duffy noted that none of the recently updated technology failed on Friday and called on Congress to approve an additional $50 billion in funding to finish a complete system overhaul.

“I’m going to say it a million times: Congress has to give the resources to the president so he can finish this build,” Duffy said.

Duffy praised Trump for his interest in updating the aging infrastructure, saying “what’s just unique about the president is he loves aviation, he loves the airspace.”

The president did not issue any statements on the ground stop Friday or appear at either of the White House’s two emergency news conferences. When asked by a reporter about the president’s silence, Duffy said that Trump was “fully engaged” and had been in communication with his relevant Cabinet members throughout the duration of the ground stop.

Homeland Security Secretary Markwayne Mullin said there is no evidence that the telecommunications outage was the result of a cyber attack or any nefarious foreign actors. However, he did say that the country’s outdated air traffic control system itself was a national security risk.

“Our air traffic control system is outdated, and it hasn’t been a priority from Congress,” Mullin said. “This is what happens when Congress kicks the can down the road.”

Mullin noted that the communications failure was caused as the FAA was performing upgrades.

“That new equipment, new technology — it was overwhelming the older system,” he said. “The patchwork doesn’t work. We need one complete system.”

In the initial absence of answers, speculation was raised over whether the ground stop was tied to the use of an AI tool that assists air traffic controllers.

The FAA expanded the use of the tool to all of its 22 control centers on Tuesday, according to the agency. The tool — called Strategic Management of Airspace, Routes and Trajectories, or SMART — combines about 200 data streams, including flight paths, schedules and weather, on one cloud-based system, according to a fact sheet posted on the FAA’s website.

Congressional Democrats raised concerns after the platform’s initial roll-out in the Washington area, calling for a 90-day pause until they better understand how it is being used. In a letter to Duffy, lawmakers said there was an “egregious lack of transparency” about the tool.

“The air traffic control systems and processes currently in place are complex, and we don’t know what impact AI-enabled tools might have on these systems and resulting safety,” they wrote in October.

But in a post on social media Friday afternoon, the AI company that created SMART, Air Space Intelligence, said that the “current ground stop is not based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC.”

After some questioned whether this week’s Microsoft outage could have affected the air traffic control system, Mullin said there was no connection.