A national airline had an unusual passenger for a trans-Atlantic flight - a 6-tonne, 43ft-long, 66-million-year-old Tyrannosaurus Rex holding a Dutch passport.

The fossil -- one of the best-preserved dinosaur skeletons in the world -- was transported from Chicago's O'Hare Airport to Amsterdam's Schiphol Airport by Dutch national airline KLM.

The female T-Rex, nicknamed "Trix", was hauled onto the Boeing 747 after she was excavated in the US state of Montana by a team from the Naturalis Biodiversity Centre in the Dutch city of Leiden.

Perhaps the most unusual cargo ever to be transported on a plane, it shared the remarkable flight with some 250 ordinary passengers.

Marcel de Nooijer, Executive Vice President of KLM Cargo said it was a great honour to transport "the historic queen of dinosaurs".

He said: "Our specialised employees took the utmost care transporting Trix."

And the fearsome creature which featured in the Jurassic Park hit film franchise was even given a brand-new passport by the Dutch authorities.

Trix lived some 66million years ago in what is now western North America, on what was then an island continent known as Laramidia.

It is one of the biggest predators to have ever walked the earth.

Dr Anne Schulp, head of the Tyrannosaurus Rex research department at Naturalis was pleased to finally welcome the skeleton to the Dutch city of Leiden.

She said: "When we started the search for a Tyrannosaurus Rex, I could not have imagined us finding such a remarkable and distinctive individual."

Trix is said to be a unique find.

With almost 80 percent of her bones found and their unique quality, she is said to rank in the top-three of best Tyrannosaurus skeletons in the world.

Naturalis Director Edwin van Huis said: "If there is one dinosaur that everyone wants to look in the eye, it is the fierce predator Tyrannosaurus Rex."

The skeleton will be ready for public viewing at the end of 2018 in the new dinosaur hall of the museum in Leiden.

The T-rex mission came as two mammoth tusks and other remains were unearthed in Austria, in another exciting palaeontological breakthrough.