A man has been fined $1700 after boarding two domestic flights using a false name, triggering a police response when he allegedly made a bomb reference during one of the trips.

The 45-year-old man from Brisbane pleaded guilty at the Downing Centre Local Court in NSW on July 15 to two federal offences relating to the use of false identities when flying.

He admitted to taking a flight under the guise of a constitutional flight, using false identification information to obtain the ticket and using false identification at a constitutional airport, Australian Federal Police (AFP) said.

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The man came to their attention in January, when he was allegedly overheard mentioning a bomb on his mobile phone after boarding a flight from Sydney to Brisbane.

Officers removed him from the plane before it departed and discovered he had also flown from Hobart to Sydney earlier that day under the same false name.

A search of the aircraft found no explosives and the allegation could not be substantiated.

Detective Acting Inspector Trevor Robinson said travelling under a false identity puts passengers and aviation staff at risk.

“To ensure the safety of all passengers and crew on aircraft, it’s critical we know who is actually onboard,” he said.

“We have seen instances where people use fraudulent identities to evade law enforcement and travel interstate to facilitate criminal activity.”

The AFP said it continues to work closely with airlines to detect and prevent potentially threatening security breaches.

Passengers are urged to report suspicious behaviour, including attempts to avoid screening, leaving bags unattended, loitering, erratic behaviour, concealing identity or photographing security cameras and fences.

The public is encouraged to follow the “See it. Hear it. Report it.” approach to help keep airports safe, reporting any suspicious activity to Airport Watch on 131 237 (131 AFP).