WASHINGTON, Nov 14 — The United States yesterday lifted an hours-long ground stop at the nation’s airports, with top officials explaining that the disruption was due to old equipment and not a cyberattack or sweeping Microsoft outage.

Transportation Secretary Sean Duffy told a late-night briefing at the White House that US airspace was now “opened up,” while warning it would take time for the travel chaos to clear.

“At 8:15 tonight Eastern Time, we’ve opened up the airspace,” Duffy said. “Now does that mean every flight is going to fly right now? It’s going to be slow.”

The breakdown came a day after Duffy and the White House had formally asked Congress for $30 billion to upgrade and modernize the US Air Traffic Control System.