United Airlines has resolved a technology issue that caused the grounding of hundreds of flights across the United States on Wednesday, though residual delays are expected. The airline confirmed the problem affected its Unimatic system, which provides critical flight information to other systems, including those for weight and balance calculations and flight time tracking.
Ground stops were issued at major United hubs, including Newark, Denver, Houston, and Chicago, according to the Federal Aviation Administration. The US Transportation Secretary, Sean Duffy, clarified on social media that the issue was specific to United's operations and not related to the broader air traffic control system.
United treated the technology issue as a controllable delay, meaning it will cover customer expenses such as hotels where applicable. As of Wednesday evening, tracking site FlightAware reported that 1,038 United flights—34% of the airline's schedule—had been delayed.
The incident follows a similar IT outage at Alaska Airlines earlier this year, which grounded its fleet for three hours. In April 2024, Alaska also faced a grounding due to a problem with its weight and balance calculation system.
