The Malev jet was forced to make an emergency landing in Istanbul, by which time the man had died.

The passenger - identified as Finnish national Mikaeinar Peterson by Turkey's Anatolia news agency - had been harassing people on board the flight from Bangkok to Budapest.

He allegedly punched a pilot and tried to choke an attendant.

The crew and passengers tied him to his seat and a doctor on board gave him an injection.

An autopsy carried out later in the day showed the man had died because of a mixture of the tranquilliser, and either another drug or alcohol.

Witnesses said they saw the man take a pill before he became violent, and authorities suspect he was drunk.

The crew and the doctor are being interrogated at the airport.

A new crew from Hungary was expected to fly the jet to Budapest with 189 other passengers later on Saturday.

The incident comes after a spate of 'air rage' incidents in the last few months involving disruptive and potentially dangerous passengers.

In October, an Airtours air hostess was attacked with a vodka bottle by a violent passenger on a flight from London to Malaga, Spain.

Fiona Weir from London needed 18 stitches and underwent an operation to remove a piece of glass embedded in her head.