Alaska Airlines said that around 11 p.m. ET it experienced an “IT outage that resulted in a temporary, system-wide ground stop for Alaska Airlines and Horizon Air flights.”

By Hanna Park, CNN

Published Jul 21, 2025 5:37 AM EST | Updated Jul 21, 2025 5:37 AM EST

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Alaska Airlines planes are seen at Anchorage airport on Monday, in Deadhorse, Alaska. (Photo credit: Jenny Kane/AP via CNN Newsource)

(CNN) — Alaska Airlines said its operations have resumed after a temporary ground stop was issued on all its flights and those of a regional subsidiary Horizon Air due to an IT outage, the company said Sunday evening.

Alaska Airlines said that around 11 p.m. ET it experienced an “IT outage that resulted in a temporary, system-wide ground stop for Alaska Airlines and Horizon Air flights.”

Horizon Air is the Alaska Air Group’s subsidiary serving mainly the Pacific Northwest and Alaska.

The Federal Aviation Administration’s website said late Sunday the request to ground all Alaska Airlines mainline flights was made around 10:52 p.m. ET.

As of 2 a.m. ET Monday, “the ground stop has been lifted, and our operations have resumed,” the airline said in a statement to CNN.

This is the airline’s second fleet grounding request for its mainline and Horizon flights in just over a year, following a system upgrade issue in April 2024.

Alaska Airlines did not detail the cause of the IT outage on Sunday, but warned of delays and advised travelers to check their flight status before heading to the airport.

“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,” the airline said in a statement. “We apologize to our guests for this inconvenience.”

The ground stop left some passengers stranded on planes for hours. Video from a passenger aboard a grounded flight at Seattle–Tacoma International Airport shows travelers waiting to deplane as a crew member is heard apologizing on the PA system and calling it a “very, very frustrating night.”

“As soon as we landed, we moved to the middle traffic lane, and they let us know there was a malfunction in the computer system,” Chris Fabregas, a passenger who had flown in from Nashville, told CNN. Fabregas said passengers were eventually allowed to deplane after waiting more than three hours.

Photos shared by a passenger on social media showed crowds stranded at the Seattle-Tacoma International Airport. The passenger, who was traveling back to Indianapolis after a bachelorette party, told CNN she eventually boarded a flight after being stuck for more than three hours and enduring “five gate changes.”

A ground stop is an air traffic control measure that restricts certain planes from taking off and requires them to remain on the ground, according to the FAA, causing potential travel disruptions and delays.

Alaska Airlines said in April it operates 238 aircraft under its primary brand, all Boeing planes, and 45 under Horizon Air. It is the fifth-largest airline in the US, according to its website, and serves over 120 destinations across five countries, catering to more than 44 million passengers a year.

This story has been updated with additional information.

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