Alaska Airlines and its regional subsidiary, Horizon Air, requested a ground stop to all flights Sunday night because of a computer system outage. The request to federal authorities kept Alaska and Horizon flights out of the air until the Federal Aviation Administration said the stop was lifted after 2 a.m. ET. Monday.

Alaska Airlines has resumed flights after the failure of a critical piece of hardware forced the airline to ground all its planes for approximately three hours.

Alaska Airlines stated that the IT outage resulted in a “temporary, system-wide ground stop for Alaska Airlines and Horizon Air flights” around 11 p.m. ET and lasted until 2 a.m. Monday, the airline wrote in a statement on X.