The reason for the grounding, late on Sunday, was not immediately clear. Alaska Air said on its website that it was “experiencing issues with our IT systems.”
The reason for the advisory, issued late Sunday, was not immediately clear. It initially only affected the over 200 aircraft under the Alaska Airlines brand name but was then expanded to include Horizon Air planes.

“We are experiencing issues with our IT systems. We apologize for the inconvenience and are working to resolve the issues,” Alaska Airlines said in a short statement on its website early Monday.
As of April 24, Alaska Airlines said it operated 238 planes, all Boeings, under its brand, and another 45 planes under the Horizon Air brand.
Neither Alaska Airlines nor the F.A.A responded immediately to requests for comment.
