United Airlines said that an outage on Tuesday, September 5 that temporarily grounded all of its departing flights nationwide was caused by a software update. The Federal Aviation Administration implemented a ground stop at United's request that lasted an hour. Flights already in the air were not affected. The airline emphasized that it was not a cybersecurity issue. Over 350 United flights were delayed, around 13% of their schedule for the day, impacting many Labor Day holiday travelers. United's stock price dipped 2.5% on the day following news of the ground-stop outage.