Videos posted to social media show black smoke billowing from the structure as emergency responders worked to contain the blaze.

"We're not sure if it was a hybrid or not," aviation authority CEO Mark VanLoh said. The state Fire Marshal's Office and agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are on the scene for the investigation.

The Jacksonville Aviation Authority is expected to get an update at its meeting Monday morning after a devastating fire broke out Friday in the hourly parking garage at Jacksonville International Airport.

Jacksonville International Airport has resumed flight operations but travelers are urged to seek off-site parking alternatives after Friday's fire.