On August 6, 2025, a malfunction in United Airlines’ Unimatic system disrupted air travel across the United States, causing extensive delays and cancellations. The platform, which provides essential data such as aircraft weight and balance and flight schedules, stopped functioning for several hours in the evening. This technical failure resulted in over 1,000 flight delays and more than 200 cancellations, according to aviation tracking data from FlightAware. Data indicated that 35% of United Airlines flights experienced delays and 7% were canceled on that day, while Chicago O’Hare International Airport reported 42 cancellations, most of which involved the airline. The disruption extended beyond domestic hubs in Denver, Newark, Houston, and San Francisco to international routes serving cities including London, Frankfurt, and Munich. The cause of the outage has not been disclosed, but service was restored later the same night.

By August 7, 2025, United reported gradual recovery, although 11% of its flights still faced delays and 5% were canceled. The airline released a travel advisory stating that flights to and from over a dozen U.S. and international airports might continue to face disruptions, while the Federal Aviation Administration reported that it was coordinating with the carrier to address the backlog. United confirmed that the outage was not related to cybersecurity issues and offered to reimburse certain passenger expenses, such as accommodation. Aviation specialists observed that the incident underscored the vulnerability of integrated airline systems and the imperative for robust contingency planning. The event has intensified discourse on system resilience and the necessity for operational redundancy in critical transport networks.