There was an unscheduled stop in Knoxville Tuesday evening for dozens of airline passengers headed to Chicago.
A United express plane operated by Express Jet landed safely at McGhee Tyson airport around 6:30 in the evening.
A spokesperson said it was on the way to the windy city from Columbia, South Carolina, when the flight crew reported smoke in the cockpit. They declared an emergency as a precaution.
The airline said the 28 passengers would be put on another flight to Chicago.