When was the last time the U.S. had a nationwide ground stop?

All flights across the United States were grounded Friday afternoon after the Federal Aviation Administration (FAA) said there were communications problems at regional air traffic control centers.

Transportation Secretary Sean Duffy said there was a “communication issue impacting all Air Route Traffic Control Centers,” and added that FAA technicians were “investigating the issue.”

Friday’s nationwide ground stop since Jan. 2023, when a key FAA computer system malfunctioned. Before that, the last time a nationwide ground stop was in effect had been after the Sept. 11, 2001, terrorist attacks.

Those are the only other two times the FAA has ever issued a nationwide ground stop before Friday.