Screaming passenger just wanted upgrade

An Israeli man who threatened to kill everyone on board a Qantas flight reportedly did so because he was unhappy with his economy seat.

Passenger David Peace told News Limited the man requested to be moved to business class because he didn't want to sit in economy during Thursday's flight, and when that was denied he asked to sit in the cockpit with the pilot.

He said the man then began shouting that he would kill everyone by opening the door of the plane.

Qantas staff detained the man and he was taken off the plane by police in Hong Kong.

The plane has now reportedly landed safely in London.

- AAP