The couple who died have been identified in media reports as former commercial pilot David Maddern and his wife Jan, both in their 60s.
The midair collision happened when a Jabiru J430 was taking off from one runway as a Piper Pawnee came in to land on a crossing runway at Caboolture aerodrome about 10.30am on Friday.
Fire and and ambulance crews responded, the couple in the Jabiru suffering fatal injuries and the other pilot, believed to be in his 70s, surviving with minor injuries.
Police Superintendent Paul Ready said the collision occurred "low to the ground" at the eastern end of the airfield.
"It is an incident between two planes that has been a loss of life which is tragic," he told reporters on Friday.
Supt Ready said the surviving pilot was assisting investigators and was "probably quite lucky when you look at the damage on the ground".
Queensland Ambulance Senior Operations Supervisor Matthew Davis described the scene as "incredibly confronting".
"Any incident involving the loss of life, particularly under these circumstances, is extremely, extremely difficult and hard, obviously, for the first responders and most importantly for the family," he said.
Australian Transport Safety Bureau is investigating crash, with additional expertise due to arrive from Canberra on Saturday morning.
The airfield caters to general aviation and ultralight aircraft and is not controlled by Airservices Australia.
A spokesman confirmed the aircraft involved were registered and not linked to the gliding club based at the airfield.
