The Federal Aviation Administration issued a ground stop for all Alaska Airlines flights Wednesday morning, halting departures nationwide for both the Seattle-area company and Horizon Air, a subsidiary of Alaska Air Group.

Alaska Airlines told HuffPost that a software upgrade was to blame. Though the issue was resolved by 8:30 a.m. Pacific time, the airline said that it expects flight delays to persist throughout the day.

This morning we experienced an issue while performing an upgrade to the system that calculates our weight and balance, an Alaska Airlines spokesperson said in an emailed statement.

Out of an abundance of caution, we requested a ground stop for all Alaska and Horizon flights, which was instituted at approximately 7:30am PT. The issue was mitigated and the ground stop for Alaska and Horizon flights expired at 8:30am PT.

The airline encouraged travelers to check the status of their flights either online or in its app before they head to the airport.