United Airlines Outage Grounds Flights, Hundreds Canceled

On August 6, 2025, United Airlines experienced a critical failure in its Unimatic system, which manages core flight operations and feeds into other vital systems, leading to a nationwide ground stop. The outage primarily affected major hubs such as Newark, Denver, Chicago, and Houston, resulting in over 1,000 delays and hundreds of cancellations. Although United resolved the issue by late Wednesday, residual delays and cancellations continued into Thursday. The Federal Aviation Administration and U.S. Transportation Secretary Sean Duffy confirmed the incident was isolated to United and not related to cybersecurity or the broader air traffic control system. United classified the event as a controllable delay and provided compensation such as hotel stays and meals. The incident has highlighted the increasing vulnerability of airlines to IT system failures.