Two light planes have collided midair over a regional Queensland airfield.
Grave fears are held for the occupants of both aircraft after the accident at the Caboolture aerodrome, north of Brisbane.
Emergency services were called just after 10.30am on Friday.
Police have been unable to confirm the number of passengers on board.
Queensland Ambulance and firefighters responded to a "significant incident" with paramedics assessing "multiple patients".
Investigations are under way and police are expected to hold a briefing later on Friday.
Caboolture Airfield caters to general aviation and ultralight aircraft and is not controlled by Airservices Australia.
A spokesman from the airfield confirmed the aircraft involved were registered and not linked to the gliding club based at the airfield.
He declined to comment on the incident.
The Australian Transport Safety Bureau will investigate the collision.
© AAP 2023