United Airlines Grounds Flights Nationwide Due to Technology Glitch

On the evening of August 6, 2025, United Airlines experienced a significant technology disruption that led to the grounding of its mainline flights across numerous U.S. airports. The issue, which began around 7:30 p.m. ET, impacted major hubs including Newark, Denver, Houston, Chicago, and San Francisco. By 9:45 p.m. ET, approximately 31% of United's flights were experiencing delays, with a small percentage facing cancellations. The airline identified the problem as stemming from its Unimatic system, which manages critical flight information such as weight and balance calculations and flight times.

United confirmed that the issue was resolved and that its teams were actively working to resume normal operations and assist affected passengers. A spokesperson stated, "We are working with customers to get them to their destinations after a technology disruption on Wednesday evening. The underlying technology issue has been resolved, and, while we expect residual delays, our team is working to restore our normal operations." As of Wednesday evening, FlightAware data indicated that 1,038 United flights, or 34%, were delayed. U.S. Transportation Secretary Sean Duffy noted that the issue was specific to United's operations and not related to the broader air traffic control system. United Airlines has indicated that it will treat this as a controllable delay, potentially covering customer expenses such as accommodation.

This incident echoes similar technological failures in the aviation sector, highlighting ongoing challenges with complex IT infrastructure. A report from FLT Academy in June 2025 highlighted the need for modernization of air traffic control hardware and software, much of which predates the internet era. Additionally, a 2025 Allianz Risk Barometer identified cyber loss as a primary concern for 38% of industry respondents, with incidents like the August 2024 ransomware attack on Seattle-Tacoma International Airport serving as reminders of these vulnerabilities.