Charleston International Airport officials say operations are slowly catching up and all equipment and services are now in full operation.
Federal Aviation Administration officials had to run tests Friday morning on the airport's VOR system, an in-flight instrument that helps planes land when visibility is poor. That malfunction coupled with heavy fog meant all incoming and outgoing flights were suspended Thursday night.
According to the FAA, the VOR system went down Thursday afternoon.
Charleston Airport Official, Becky Beamon, said flights were diverted to Savannah and Columbia. Some passengers were booked into local hotels for the night. At least 12 flights were affected Thursday night, and at least five were affected Friday morning.
Airport officials advise passengers to check with their airline before arriving at the airport.