FAA lifts ground stop after four hours, but flight cancellations will stretch into the weekend

The Federal Aviation Administration lifted a nationwide ground stop that lasted for more than four hours Friday.

The agency had halted thousands of departing flights across the country on Friday afternoon, a rare measure, blaming communications issues that affected "multiple" air traffic control centers. More than 10,000 flights were disrupted.

Airlines including JetBlue Airways, however, had canceled hundreds of flights because of the disruption. More flight cancellations were expected to stretch into Saturday.

Homeland Security Secretary Markwayne Mullin said Friday at the White House that there was no indication that the issues were a threat to the United States.

The FAA said in post on X that there was a "temporary telecommunications outage" and that it halted flights out of an "abundance of caution." The issues were related to communications and radar problems, according to an internal message from Alaska Airlines , which was seen by CNBC.

Airlines said en route flights would continue, but carriers were preparing to cancel flights as the disruption wore on. JetBlue Airways told staff it would cancel the remainder of the day's flights, aside from European routes, as well as others scheduled for Saturday so that crews and planes are in place to resume operations, according to a memo seen by CNBC.

FAA administrator Bryan Bedford had a call with airline CEOs around 6 p.m. indicating that it was unclear when the situation would be resolved, according to people familiar with the matter.

As of 5:56 p.m. ET, some outbound international traffic was in the air, according to Flightradar24, flight-tracking site. That included a Lufthansa flight from Boston to Frankfurt, Germany, that departed at 5:21 p.m. ET and an ITA Airways flight from Boston to Rome that left at 5:24 p.m. ET, according to the site.

As of 6:50 p.m. ET, cargo and passenger flights were also departing the West Coast for Asia and Hawaii.

Flights will be allowed to depart as en route traffic facilities recover, "through coordination with the air traffic control system," the FAA said at about 6 p.m..

Technical issues have repeatedly snarled air traffic in the U.S. in recent years.

In September, hundreds of flights into Newark, New Jersey, and Philadelphia were canceled, delayed or diverted after a Verizon fiber cable was accidentally cut. Officials said it occurred during construction in New Jersey, severing a backup feed of key data for air traffic controllers.

In 2025, air traffic controllers lost contact with aircraft heading to and from Newark Liberty International Airport, an equipment failure that led to massive flight delays and raised more concerns about aging U.S. aviation infrastructure and staffing shortages.

It wasn't immediately clear what caused Friday's problem.

Inbound international flights will be managed on a case by case basis, the FAA said.

The major U.S. airlines issued statements saying they would work with customers who were affected by the ground stop and encouraged travelers to check for updates.

— CNBC's Kevin Breuninger and Phil LeBeau contributed to this article.

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