United Airlines flights resumed slowly after a nationwide outage following a technology issue that forced the airline to ground its mainline fleet on Wednesday.

Tech outage causes flight disruption
United Airlines faced a major tech issue that affected multiple flights across the United States. The issue was flagged by the United States Federal Aviation Administration, which stated that the airline’s flights headed for Chicago had been grounded. The issue also affected Denver, Newark, Houston and San Francisco flights.
The FAA had said in an initial statement:
“We’re aware United experienced a technology issue disrupting their operations. Some delays may continue as they work through the recovery process. We’ve offered full support to help address their flight backlog and remain in close contact with United,”
Sean Duffy, Secretary of the US Department of Transport, had further clarified that he had spoken to United CEO Scott Kirby about this “on their company’s internal tech outage.” The problem only affected United and was not related to the broader air traffic control system.
“The team is in close contact with their systems operations team, and we’ve offered our full support to help them clear up the flight backlog,” Duffy had said.

United says flights resuming
United Airlines, in a statement to the media, had said that though it expects residual delays, it is working on restoring operations after resolving the tech issue. According to media reports, the issue was with its Unimatic system, which is responsible for storing flight information and feeding it to other systems.
As of 3:15 a.m. ET, 110 United flights were cancelled while 103 were delayed following the tech outage as per flight tracking platform FlightAware.
In a query regarding flight disruption at Newark airport on X, United had responded:
“Due to a technology outage, we are temporarily holding some United flights at their departure airports to manage gate availability at destination airports. This may result in delays throughout the evening as we work to resolve the situation.”
The airline would help with customer expenses, such as hotels, where applicable, while treating the issue as a controllable delay.
In answer to a query from a customer on the X platform, regarding delays at Denver, the airline had responded:
“A nationwide outage is affecting flights, including in Denver, and our teams are working nonstop to restore service.”
This incident comes shortly after an air traffic control fault had led to the grounding of departure flights across the UK.
Were you affected by this outage? Please do share your experience in the comments.