More than 30 firefighters have contained a blaze at a flight training facility at Parafield airport, north of Adelaide.
The Metropolitan Fire Service (MFS) said 12 trucks were sent to the fire.
"The incident was called in by multiple triple-0 callers just prior to 7:00am ... advising an air conditioning unit was on fire on the roof of the building," a spokeswoman said.
The fire quickly spread throughout the building on Kittyhawk Lane.
Fire and Rescue authorities said they rescued a person who was trapped in a car.