The Horizon Air (QX/QXA) brand has migrated to parent company Alaska Airlines. It will still remain a separate entity, but the Alaska Airlines livery will be adopted with the Horizon titles integrated on their Dash8-Q400 fleet. On board, the Horizon experience will not change.
The Alaska Airlines/Horizon Air press release.
Pictured above, is Horizon's Dash8-Q400, N411QX (msn 4055), on final approach for LAX's Runway 24R, taken in November 2010.