A medical science student's Instagram threat to blow up a plane because of a three-hour delay would have led to jail time if possible, a magistrate has said.
Andre La Guardia, 22, made the fateful post at Sydney International Airport after finding out a flight with his family to the Philippines had been delayed for a few hours.
"Imma bout to blow this s*** up," he wrote while waiting for the flight in a post showing the interior of an aeroplane containing passengers.
Instagram quickly removed the post for breaching community standards and referred the matter to the Australian Federal Police.
The December 19 flight took off without incident with La Guardia allowed into the Philippines after speaking with police on arrival.
On his return to Sydney on January 17, La Guardia was interviewed by police and charged with threatening aviation security.
Facing Downing Centre Local Court on Wednesday, the 22-year-old pleaded guilty as his lawyer urged the court not to convict.
While it was no defence to the crime, La Guardia had not actually intended to follow through with the threat, solicitor Paul Meehan said.
The 22-year-old had his whole life ahead of him, including a medical career and dreams of travelling.
"It was an expression of frustration by a naive, young man who has now certainly learnt his lesson," Mr Meehan told the court.
But Magistrate Greg Grogin underscored that bomb threats were no joke.
He convicted the student and imposed a $10,000 fine while lamenting how parliament had made the offence fine-only.
"To suggest that something is going to be blown up, particularly an aircraft, is an absolutely unbelievably stupid and unacceptable thing to do," he said.
"If there was a jail term, Mr La Guardia, you would be receiving a term of imprisonment from me."
He noted that the student had accepted accountability for his actions through his co-operation with police, his early guilty plea and a letter of apology to the court.
But a message needed to be sent to others not to make the same type of comments, Mr Grogin said.
The magistrate urged people to imagine the panic and fear the captain would have felt when told there was a threat to blow up their plane.
"Luckily, it would appear the crew kept their heads," he said.
La Guardia was supported by his parents, sister and brother-in-law in court.
Talking to reporters outside, the young man apologised to those on the plane and said he regretted his actions.
The maximum penalty for threatening aviation safety is a $16,500 fine.
