A technology issue which led to the grounding of United Airlines’ flights for a few hours on August 6, 2025, has been resolved, after causing major delays across the airline’s network.
United said the issues impacted a system named Unimatic, which houses information about each flight that is then fed to other systems including those that calculate weight and balance and track flight times.
A spokesperson for the airline confirmed to Airline Economics that the outage began at 5:12 pm CDT and was resolved within a few hours, although residual delays continued into the night.
The technology issue prompted ground stops at several major United hub airports including Newark, Denver, Houston, and Chicago, according to the US Federal Aviation Administration.
US Transportation Secretary Sean Duffy said in a post on X that he had been briefed by United CEO Scott Kirby on tech outage, stating that the issue was specific to United’s operations, and is “unrelated to the broader air traffic control system”.
United said it was treating the technology issue as a “controllable delay”, meaning it would pay customer expenses such as hotels when applicable.
The airline also confirmed that this outage was not related to recent concerns about cybersecurity in the airline industry.