Thousands of passengers have had travel plans plunged into chaos after Alaska Airlines was forced to ground all its planes after an IT outage.
The carrier experienced an "outage that resulted in a temporary, system-wide ground stop for Alaska Airlines and Horizon Air flights" at around 8pm Pacific time on Sunday (4am Monday UK time).
It later said that operations had resumed and the system had been out for approximately three hours.
But it said: "As we reposition our aircraft and crews, there will most likely be residual impacts to our flights. It will take some time to get our overall operations back to normal”.
"Please check the status of your flight before leaving for the airport," it added.
Details of what casued the outage have yet to be specified.
It remains unclear whether Alaska's outage is related to Microsoft stating on Sunday that there were "active attacks" on its server software used by government agencies and businesses.
Alaska Airlines has resolved its earlier IT outage and has resumed operations. We sincerely apologize for the inconvenience, and encourage guests to check your flight status before heading to the airport.
— Alaska Airlines (@AlaskaAir) July 21, 2025
Alaska did not immediately respond to a request seeking comment on whether the outage was related to the Microsoft announcement.
The Federal Aviation Administration website had confirmed a ground stop for all Alaska Airlines mainline and Horizon aircraft.
Horizon Air is the regional subsidiary operating Alaska Airlines flights.
Alaska Air Group maintains an operational fleet of 238 Boeing 737 aircraft and 87 Embraer 175 aircraft, according to its website.
In June, Hawaiian Airlines, which is also owned by Alaska Air Group, said some of its IT systems were disrupted by a hack.
In September, Alaska Airlines said it grounded its flights in Seattle briefly due to "significant disruptions" from an unspecified technology problem that was resolved within hours.
