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

JUST IN: The FAA has lifted its nationwide ground stop after four hours, but flight cancellations will stretch into the weekend, officials say.

American skies are open again, after four hours of nationwide shutdown.

The FAA lifted its ground stop at 8.15 in the evening Eastern time, blaming a temporary telecommunications outage that hit multiple air traffic control centers at once. More than 10,000 flights were disrupted, around 600 were diverted, and you can see what that looks like here, terminals full of people going nowhere.

Homeland Security Secretary Markwayne Mullin says there's no sign of a cyber attack, that this appears mechanically driven. Transportation Secretary Sean Duffy points at aging air traffic control infrastructure, the same system officials have been warning about for years.

Lifting the stop doesn't end the pain. JetBlue has already cancelled the rest of Friday's flights and Saturday departures too, just to get crews and planes back where they belong. This was only the second nationwide ground stop since September 11, and it happened because the phones broke. That is the state of the system carrying 11,000 departures a day.

This is Kateryna Kovalenko, reporting for HIT.