IT wasn't a scene from a Hollywood blockbuster when passengers on a Qantas flight from Cairns to Port Moresby looked out the window of their airborne aircraft and saw a 3m snake clinging to the wing.

The amethystine python scaled new heights when it hitched a ride on the Bombadier 400 aircraft.

But unlike Snakes on a Plane, the 2006 thriller, starring Samuel L Jackson as an FBI agent, there was no danger to anyone inside the aircraft.

It was not long into the flight early Thursday morning before a passenger saw the snake and raised the alarm.

There was nothing anyone could do to help the stricken python in the chamber just a short distance from Qantas's famous flying kangaroo logo.

Altitude was taking its toll as well as freezing temperatures and the high speed of the aircraft.

Passengers could only watch on as the animal's tail was whipped against the rear end of the plane, the impact creating a blood trail, part of which in the photo looks like a tear in the plane's fuselage. The python was dead on arrival when QF191 touched down at Port Moresby at 7.44am with 40 passengers and four crew on board.

A crew member said that when the python's presence was first reported the initial reaction was "you gotta be kidding?''

The crew member said there was a lot of commotion on the ground after the plane landed in Port Moresby

"The python didn't quite make it out alive, especially with some flap extension for landing,'' he said.

Qantas yesterday said hitchhiking pythons were not an everyday occurrence.

"We have never heard of this happening before,'' a spokesperson said.

"The python must have taken refuge on the exterior of the aircraft at Cairns Airport overnight before take off.''

The python was handed over to quarantine officials in Port Moresby.

Herpetologist and James Cook University graduate David Williams divides his time time between the University of Melbourne's School of Medicine's Venom Research Unit and the School of Medicine and Health Sciences at the University of Papua New Guinea in Boroko. He identified the unfortunate hitchhiker as an amethystine python.

"These occur in the Mt Whitfield area directly opposite Cairns airport and probably also in the mangroves that surround the airport,'' he said.

Amethystine pythons can grow to 8.5 metres in length and are Australia's largest snake.

Originally published as Seriously, snakes on a plane