United Airlines says outage that held up departing flights was not a cybersecurity issue

United Airlines said Tuesday that a software update triggered a glitch that forced it to halt departures nationwide, briefly crippling one of the nation’s biggest carriers on a busy travel day.

Federal officials said United crews had been unable to contact airline dispatchers through normal means. “A software update caused a widespread slowdown in United’s technology systems,” United UAL, -2.51% said in a statement. The airline said it was not a cybersecurity issue.

The Federal Aviation Administration, which runs the nation’s airspace, said United asked it to stop the airline’s departures nationwide. The FAA said the issue was limited to United and its subsidiaries. The ground stop — it did not affect planes already in the air, United said — lasted a little more than an hour.