The North-East student jailed for a drunken threat to hijack an Australian plane promised last night that he would never fool around on an aircraft again.

Tom Lilico promised that from now on ''it is strictly tape over the mouth'' whenever he is on an aircraft after emerging from prison in Australia.

The 22-year-old, from Darlington, County Durham, served two weeks of a one month sentence at the Lotus Glen Correctional Centre near Cairns.

A judge used new anti-terrorist legislation to send him to jail after he was overheard by a Qantas flight attendant on a January 1 domestic flight saying he was going to pull a knife and hijack the plane.

Mr Lilico said he had drunk so much he couldn't remember making the remarks.

''I can't remember saying the comment that was alleged,'' he said, although he had admitted in court to making threatening comments.

''I didn't have a knife with me so I have no idea why I would say something like that.'' Lilico was asleep by the time security staff came to remove him from the plane, which had been set to take off for Darwin.

He later told police he had consumed eight pints of beer in the hours before the boarding the aircraft.

He said he ''nearly collapsed'' when the prison sentence was handed down to him, but that he had been treated well in jail.

''The inmates found it really funny. At the same time, a lot of them were sympathetic and thought I shouldn't have been there,'' he said.

Lilico, a fine arts graduate who had planned to stay in Australia until March on a working holiday, said he may head home sooner than expected.

''Obviously, there is a lot of paranoia about these sorts of things at the moment and (the authorities) are not to know whether somebody is being serious or not,'' he said.

Lilico was the first person jailed in Australia since September 11, 2001, for making threatening comments on board an aircraft.

''I am relieved it's all over,'' he said. ''I have just got to put it down to a life experience and move on. But it's strictly tape over the mouth now when I get on a plane.'' .