United Airlines Outage Grounds Flights Nationwide

On August 6, 2025, United Airlines suffered a nationwide disruption after a critical failure in its Unimatic system, which manages core flight operations. The outage grounded all United mainline flights at major hubs including Chicago, Denver, Newark, Houston, and San Francisco, resulting in over 1,000 delays and more than 40 cancellations. The Federal Aviation Administration imposed ground stops at key airports, while United resolved the issue within a few hours by late evening. Despite the quick fix, widespread delays and backlogs continued through the night, affecting thousands of passengers. United and U.S. officials confirmed the incident was not caused by a cybersecurity attack and was limited to United's systems, with regional and in-air flights mostly unaffected. The airline offered compensation such as hotel stays and meals, stressing that passenger safety remained its top priority.