The Sri Lankan student who threatened to set off a bomb on board a flight from Melbourne to Kuala Lumpur is due to face court for a pre-sentence hearing, SBS News reported.
Manodh Marks, 26, forced Malaysia Airlines flight MH128 to turn back shortly after take-off in June 2017 when he started screaming that he had a bomb.
The student, who had been living in Dandenong, was overpowered by passengers and tied up until the flight landed at Melbourne Airport.
Police made passengers stay on the plane for almost 90 minutes before storming the aircraft and arresting Marks.
Officers copped criticism for taking so long to remove Marks, who had actually been holding what authorities called a "speaker-type" object.
Marks pleaded guilty to attempting to take control of an aircraft, which carries a maximum penalty of 20 years behind bars.
He is due to face a plea hearing in the County Court on Thursday.