By Dave Harvey
BBC Points West Business Correspondent
The Airbus A400M is expected to replace Hercules aircraft used in Iraq
It has been 26 years in the making. Arguments have raged between Europe's capitals over its design, its cost and where it should be built.
But later, in Seville, the King of Spain will unveil the Airbus A400M, built for air forces across Europe including the RAF.
A grand ceremony has been promised. Journalists, politicians and VIPs are flying in from Germany, France, Italy, and the UK.
A 50-seater plane has been chartered from Airbus UK's headquarters at Filton, outside Bristol.
But the plane will not fly on Thursday. It will not even fire its engines.
Carbon fibre wings
This is a "roll out", where the world sees the completed aircraft for the first time.
The maiden flight will occur later in the summer, but no date has yet been specified.
Airbus A400M shown to public
So why is there such a fuss about a plane that cannot even take off yet? The answer lies mainly in its wings.
It's a bit like Mrs Jones' Christmas cake....you can't be sure each one will be identical
Professor Philip Lawrence
They are made mostly of hi-tech carbon fibre and are manufactured in the UK.
There are metal elements, but there is more carbon fibre in this plane than anything Airbus has yet made.
Dave Phipps is head of Airbus' carbon fibre research department at Filton.
"Making wings out of carbon fibre cuts the fuel consumption by at least 20%," he said.
"It's a revolutionary technology. It is so much lighter, and yet just as strong and just as safe."
'Tested to destruction'
The A400M will replace the ageing fleet of C-130 Hercules that see action daily in Afghanistan and Iraq.
After two decades of political posturing and technical problems, Airbus have to get this plane right. And much will be made of its carbon fibre wings.
Professor Philip Lawrence, aviation expert at the University of the West of England, said: "Just because you're good at making planes out of metal there's no guarantee you will lead the world in carbon fibre."
The sheets of carbon fibre are "cooked" in a massive oven
Prof Lawrence has watched the development of carbon fibre aeronautics with interest.
"Everything is different," he says.
"Dealing with lightning strikes is much harder. Every time you cut a hole to fit electronics the structure of the wing is affected and joins between metal and carbon fibre can be tricky."
Boeing have already experienced problems with carbon fibre aircraft manufacture.
Every sheet must be "cooked" in a massive oven, and heat does not work exactly the same every time.
"It's a bit like Mrs Jones' Christmas cake," said Prof Lawrence. "You can't be sure each one will be identical."
But at the Airbus labs at Filton they are utterly confident.
A sample wing has been tested to destruction and is said to have passed with flying colours.
"We wouldn't put this material in the air unless we were sure of it," insisted Mr Phipps.
Journalists and VIPs flying to Spain from Filton will be using the same airfield that launched the Brabazon, the Brittania and the Concorde.
At Filton the 6,500 workers are fiercely proud of their flying heritage and what they've achieved.
But Airbus is flying into a new world, a carbon fibre world.
Its future could rest on whether the plane unveiled later in Seville flies smoothly off the production line.
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