SAN FRANCISCO, April 17 -- Alaska Airlines flights have resumed after they were grounded for an hour Wednesday morning, the company said in a statement.

In its statement, Alaska Airlines said it had experienced an issue "while performing an upgrade to the system that calculates our weight and balance."

All flights by Alaska Airlines and Horizon Air, which is owned by Alaska Airlines, were grounded from 7:30 a.m. to 8:30 a.m. local time "out of an abundance of caution," the company said.

  - Xinhua