UPDATE: It's been revealed one of the people missing after a light plane crash off South Stradbroke Island would have been celebrating her birthday today.
Emergency crews are back combing the waters for the 52-year-old male pilot and 31-year-old female passenger, after a large amount of debris from the Yak-52 aircraft washed up on a beach.
Search and Rescue Coordinator Senior Sergeant Jay Notaro from Gold Coast Water Police said the female passenger took the flight to help celebrate her birthday.
"She was a mother of an 11-year-old daughter. It's actually her birthday today," said Senior Sergeant Notaro.
"It actually was a birthday flight. The pilot was known to her and was providing that flight for her."
The air, land and sea search resumed on Thursday morning, involving specialised underwater sonar equipment.
EARLIER: Fears are growing for the pilot and passenger of a light vintage aircraft that has gone missing after a scenic flight over South Stradbroke Island.
The Yak-52 aircraft left from the Southport Flying Club at Coombabah around 10am on Wednesday for a 30 minute trip but never returned.
Air Traffic Control contacted the Australian Marine Safety Authority about 1.15pm to begin the search which involved helicopters, boats and jet skis.
Nine News has reported police confirmed a large chunk of a Yak-52 aircraft was located on the northern end of the island overnight, after a suspected part of the propeller was found yesterday afternoon.
The recovery effort of the aircraft continues this morning, as well as the search for the two people on board.