United Airlines Grounded All of Its Flights Over a Technological Issue

As one of the biggest airlines in the country, millions of people rely on United Airlines to get where they're going on a regular basis. Needless to say, then, that if United grounds all of their flights on a given day, it causes massive disruptions for travelers who are trying to get where they're going.

That's exactly what happened on Aug. 6, when United grounded more than 1,000 flights over a technical issue. Here's what we know about why the flights were grounded, and what exactly happened.

The reason United grounded so many flights is that it was experiencing technical issues with its Unimatic system, according to The Associated Press. Unimatic is apparently responsible for feeding into other systems that calculate weight and balance and track flight times. We don't know exactly what caused the problem, but it was resolved late in the day on Aug. 6, although flights on Aug. 7 continued to feel the ripple effects.

The alert first came through to ground all flights coming into Chicago, but the issue also affected some flights at the Denver, Newark, Houston, and San Francisco airports.

“Safety is our top priority, and we’ll work with our customers to get them to their destinations,” United's statement said. The airline is based out of Chicago, so it makes sense that travel there was the most directly impacted.

The company described the issue as a system outage and said that it lasted for several hours before being resolved. Thirty-five percent of the airline's flights were delayed as a result, and six percent were canceled completely.

United was responding to individual users on X (formerly Twitter), apologizing for the issue and assuring customers that the airline would help them get wherever they want to go.

“Hey there, we apologize for the travel disruption today,” the airline said. “Our teams are working to resolve the outage as quickly as possible. Thank you for your patience.”

Although the outage was widespread, there was unfortunately not much that anyone could do about it outside of United. Some fliers might have been able to find flights from alternate airlines, but many, many people just had to wait for the issue to resolve itself.

This comes during a tumultuous period more generally for the airline industry. For the most part, though, these issues have had more to do with flight safety than they have with these kinds of technological issues. A shortage of FAA staffing has led to some close calls on runways, as well as a couple of actual disasters that might have been avoidable.

What's clear, then, is that it's a precarious time to fly for any number of reasons, and that's true even as flights remain in high demand. For as inconvenient as it can be when you're wrapped up in this kind of issue, flying is typically the most convenient way to travel. Hopefully, United has resolved whatever issue it was facing and will be able to avoid similar outages moving forward.