Alaska Airlines and its regional subsidiary, Horizon Air, experienced a significant system-wide IT outage on Sunday, July 20, 2025, leading to a temporary ground stop for all their flights. The disruption, which began around 8 p.m. Pacific Time (11 p.m. ET), caused widespread delays and cancellations, stranding passengers and disrupting travel plans across the airline’s network. Operations resumed approximately three hours later, by 11 p.m. Pacific Time (2 a.m. ET) on Monday, July 21, 2025, according to statements from the airline and the Federal Aviation Administration (FAA).
The airline confirmed that the outage was triggered by the failure of a “critical piece of multi-redundant hardware” within its data centers, as reported by CBS News and Azcentral. Importantly, Alaska Airlines clarified that the incident was not related to a cyberattack, distinguishing it from a separate cyber incident that affected several carriers, including Hawaiian Airlines, last month. The FAA had issued advisories regarding the ground stop, which is an air traffic control measure implemented to prevent flights from taking off when conditions are unsafe or systems are compromised.
The immediate impact on travelers was substantial. Passengers reported being stranded on planes for hours and encountering large crowds at major hubs like Seattle-Tacoma International Airport. Videos shared by passengers depicted frustrated travelers waiting to deplane, with crew members apologizing for the “very, very frustrating night.” One passenger, Chris Fabregas, recounted waiting over three hours on a grounded flight before being allowed to deplane, while another described enduring “five gate changes” at Seattle-Tacoma before finally boarding a flight, as detailed by CNN and Fox Business.
Despite the swift lifting of the ground stop, the airline warned of ongoing “residual impacts” to its flight schedule as it works to reposition aircraft and crews. As of Monday morning, the disruption had led to a significant number of cancellations and delays. CBS News reported over 150 flight cancellations, including 64 on Monday alone. Flight tracking website FlightAware indicated 81 cancellations and 137 delays for Alaska Airlines as of 8:30 a.m. Monday, July 21, with Phoenix Sky Harbor International Airport alone seeing two cancellations and six delays, according to Azcentral.
This incident marks the second time in just over a year that Alaska Airlines has had to ground its fleet due to system issues. A similar grounding occurred in April 2024 following a system upgrade problem, and the airline also experienced a brief grounding in September due to an unspecified tech problem in Seattle, as noted by CNN and CBS News. These repeated technical difficulties raise questions about the resilience of the airline’s IT infrastructure.
Alaska Airlines, which operates 238 Boeing aircraft under its primary brand and 45 under Horizon Air, is the fifth-largest airline in the U.S. It serves over 120 destinations across five countries, catering to more than 44 million passengers annually. The airline has apologized for the inconvenience and advised all travelers to check their flight status before heading to the airport, emphasizing that it will take time for operations to return to normal.
