Residual Delays Continue After United Airlines Ground Stop Due to Technology Disruption
East Boston, Mass. – August 7, 2025 — Residual flight delays persisted into Thursday following a significant technology disruption that forced United Airlines to halt some of its flights nationwide Wednesday evening. The interruption centered on an outage in United’s Unimatic system, which calculates aircraft weight and balance and tracks flight times—an essential component for flight safety and scheduling.
Ground Stop Imposed Wednesday Evening
At approximately 6 p.m. on Wednesday, United Airlines issued a ground stop, holding all mainline flights at their departure airports while addressing the system outage. The airline released a statement emphasizing, “Due to a technology issue, we are holding United mainline flights at their departure airports. Safety is our top priority, and we’ll work with our customers to get them to their destinations.”
Flight tracking website FlightAware reported that the disruption led to delays for over 1,000 United flights and caused dozens of cancellations nationwide within just a few hours. At Boston’s Logan International Airport, the airline experienced delays affecting eight flights, some of which were grounded for more than four hours until the problem was resolved shortly after 10 p.m.
Passenger Experiences and Aftermath
Passengers across the country shared accounts of their travel disruptions. Some departing travelers reported being stuck on planes on the tarmac for over an hour before their aircraft could return to the gate. Arriving passengers were also affected, particularly at Logan International. Benjamin Fuentes, a passenger who had just landed in Boston, recounted, “We had landed and that’s when they told us we would be waiting for a while. We didn’t get any further news until about an hour into the wait, when they finally told us, ‘Oh, the whole system is down nationwide.’”
The outage affected the Unimatic system, which stores key data for each flight. This information is used by other critical systems that calculate weight and balance as well as flight times.
No Cyberattack; Incident Isolated to United Airlines
United Airlines has confirmed that this was not the result of a cyberattack. Transportation Secretary Sean Duffy clarified that the disruption was isolated specifically to United’s systems and did not impact broader air traffic control operations.
Both the Federal Aviation Administration (FAA) and the Department of Transportation are actively collaborating with United to get flights back on schedule. However, officials have warned that the ripple effects of the outage could prolong delays well into the weekend as the airline works to fully recover.
Current Situation at Logan Airport
As of Thursday morning, operations at United’s Terminal B in Logan have largely stabilized, with flights experiencing modest delays ranging from 20 minutes to around two hours. No cancellations have been reported so far for the day, and check-in lines and ticket counters are operating smoothly.
Travelers are encouraged to verify flight statuses and prepare for potential continued delays, particularly for those flying with United Airlines over the coming days.
Reporting from inside Terminal B at Logan International Airport,
Todd Kazakiewich, WCVB Boston
