On Sunday night, Alaska Airlines brought all of its flights to a standstill after a crucial piece of hardware in one of its data centers suddenly failed. The issue started when a controller card, a small but essential device responsible for coordinating communication between servers, malfunctioned. These cards are typically built with multiple layers of redundancy to prevent exactly this kind of breakdown. But in this case, not only did the main controller card stop working, but every backup failed too.

It was a rare but deeply disruptive failure that brought the airline’s systems offline all at once.

Without access to the systems needed for flight operations, scheduling, and crew coordination, the airline had no choice but to initiate a system-wide ground stop for all Alaska and Horizon Air flights. This happened around 8 p.m. Pacific time on Sunday.

While operations resumed about three hours later, the disruption had already made its impact.

Flights were canceled, passengers were delayed, and airports across the country felt the ripple effects. By Monday morning, the airline was still working to restore normal operations and reposition aircraft and staff across its network.

Why It Matters: All airlines rely on complex, layered technology to manage everything from crew schedules to flight plans. Even small components can carry big responsibilities, and when they fail, the consequences are immediate and far-reaching. This incident shows how even redundant systems can fall short when critical infrastructure is managed externally and fails in unpredictable ways. The event impacted travelers nationwide and raised new concerns about IT resilience in the airline industry.

• The Root of the Problem: The outage began when a controller card in Alaska Airlines’ data center failed unexpectedly. This piece of hardware routes essential data between systems. Although the system had multiple backups, all layers of redundancy failed at once, taking down key operational tools. Although the system was designed with multi-layer redundancy, all backup mechanisms failed in succession. The company stressed that passenger safety was never at risk, and that the problem was contained to its internal systems rather than due to a cybersecurity breach.

• Flights Halted for Hours: Alaska Airlines acted quickly to minimize risk by issuing a full ground stop at 8 p.m. Pacific time, halting all mainline and regional Horizon Air flights across the U.S. With its digital systems offline, the airline could not perform the basic functions needed to launch and manage flights safely. Although flight operations resumed at around 11 p.m., the temporary halt had already caused significant disruption. The airline communicated with customers in real time through its social media accounts and later confirmed that while operations had resumed, delays and further cancellations were likely as the system recovered.

• Major Disruption for Passengers: More than 200 flights were canceled, impacting over 15,000 travelers. Alaska’s main hub, Seattle, was hit hardest, though disruptions occurred across the country as planes and crews were left out of position. Passengers found themselves stranded, rebooked, or delayed as the airline scrambled to restore balance to its network. Because the outage left aircraft and crew scattered out of sync with their original schedules, some flight legs remained canceled even after system functionality returned.

• No Evidence of Cyberattack: Alaska Airlines confirmed that the outage was not related to hacking or external cybersecurity threats. Moving forward, the airline is expected to re-evaluate its infrastructure setup and possibly strengthen fail-safes to avoid future incidents. In the meantime, Alaska has emphasized customer support, urging affected travelers to use its flexible rebooking policy and stay updated via its website and social media channels.

Go Deeper -> Alaska Airlines resumes flights after equipment failure at a data center grounds all its planes – AP News

Alaska Airlines statement on IT outage – Alaska Airlines

Alaska Airlines reveals details of nationwide outage – Newsweek