United Airlines resumes mainline flights after brief nationwide halt due to fire alarm

United Airlines resumed all its mainline flights after a brief nationwide ground stop triggered by a fire alarm at its Network Operations Centre in suburban Chicago, Fox News reported.

The airline said operations were back to normal late Thursday after employees returned to the primary facility in Arlington Heights, where an emergency alarm had forced a temporary shift to a backup location.

"A fire alarm sounded at our operations centre, which caused employees to move to our nearby backup facility and resulted in a brief nationwide ground stop of United aircraft," United Airlines said in a statement to Fox News.


"Employees have returned to our primary operations centre, and the ground stop has been lifted," the airline confirmed.

According to the Federal Aviation Administration (FAA), the ground stop was initiated around 6:30 pm (local time) and lifted before 7:30 pm (local time).

United Airlines clarified that no flights were diverted, and its regional service, United Express, was not impacted by the issue, as per Fox News.

The airline also issued an update on X alerting passengers that some flights may experience delays due to the brief disruption.