The Federal Aviation Administration expanded its $875 million AI-powered air traffic management system, SMART, to all 22 air route traffic control centers across the United States, the agency announced on November 101,2. Three days later, the FAA ordered a rare nationwide ground stop on all departing flights, citing "extraordinary circumstances and for reasons of safety"5,6.
The cause of the ground stop remains under investigation, and no evidence has linked SMART to the shutdown4. Transportation Secretary Sean Duffy attributed the stoppage to a communications issue affecting all air route traffic control centers. Homeland Security Secretary Markwayne Mullin said there was "no indication" the event constituted a national security threat.
What SMART does
SMART — Strategic Management of Airspace — merges roughly 200 data streams covering flight paths, schedules, weather, and other factors onto a single platform to anticipate airspace constraints3. The system advises controllers on flight routing but leaves final decisions to humans.
The FAA says SMART helped reroute 180 flights after an initial deployment over Washington, D.C., airspace on September 21, saving an average of 10 minutes per flight and almost 80 gallons of fuel per flight. The agency statement on November 10 said it would now use SMART across all 22 centers "to reduce delays, reduce fuel consumption and improve the travel experience for the flying public".
Controller union excluded
The rollout has drawn scrutiny from the National Air Traffic Controllers Association, which said it was not involved in designing or testing the AI-driven system. Airline executives, by contrast, have voiced support for the deployment.
The ground stop
The FAA issued its ground-stop alert on Friday afternoon, halting all departing US flights until further notice and handling inbound international flights on a case-by-case basis. The agency said every flight had been accounted for and described the trigger as a "temporary telecommunications outage". The stoppage marks only the second full nationwide ground stop since the September 11, 2001, attacks; the most recent, in 2023, lasted about 90 minutes after a pilot notification system failed.
A source told the New York Post the stoppage was potentially caused by a software upgrade. The FAA did not immediately link the disruption to SMART.
ANALYSIS The proximity of the SMART expansion and the ground stop will intensify questions about the pace of the rollout, particularly given the controllers' union's stated exclusion from the system's design and testing process.