The US Federal Aviation Administration (FAA) stopped all flights from leaving US airports on Friday. The stop lasted for more than four hours. It was the longest stop across the whole country since the attacks on 11 September 2001. More than 3,500 planes were already in the air. Some went to other airports, but others continued to their planned airports.

The problem started in a system that helps air traffic workers speak to pilots and watch planes. Transport Secretary Sean Duffy said the old system received too much data and stopped working. Homeland Security Secretary Markwayne Mullin said there was no sign of an attack. He said people were safe.

The FAA opened the skies again at about 20:15 US Eastern Time. The problem caused more than 8,500 late flights and almost 8,000 cancelled flights. Many people had to wait at airports. Major US airlines started flights again, but JetBlue planned to restart on Saturday morning. Duffy said flight problems could continue for a few days. He also said the old system needs major work.