The airline grounded flights at all US airports on the day due to a technical issue.
The airline said in a statement that it was "experiencing an IT outage affecting flight schedules" and issued "an operational pause."
The airline did not say how long the disruption would last or how many flights were affected. It said it was "actively restoring our services" after the outage.
The operational halt also affected the regional carrier, which is operated by Alaska Airlines, according to an notice by the Federal Aviation Administration.
The airline, part of The airline group based in Seattle, Washington, mainly serves on the western seaboard of the US. It connects 140 destinations worldwide, including 37 states and 12 countries, according to its online platform.
Last year, the carrier joined forces with Hawaiian Airlines, which was unaffected by the day's flight suspension.
It is the latest IT outage impacting the airline in recent months. Earlier this year, an outage halted flights for about three hours.
The company did not immediately respond on the day to requests for comment.
Air transportation in the US has been disrupted in the past few weeks due to the US government shutdown that began earlier this month. Shortage of air traffic controllers reporting for duty has delayed flights at several airports.
