Work is in progress on an aircraft that will attempt a world's first: Flying around the world without fuel.

Test flights will take place early next year, with the around-the-world voyage - slated to take 25 days and nights - taking off in 2011.

Pulling it all together is Swiss-based Solar Impulse, in partnership with several companies and organisations, including the International Air Transport Association (Iata) - a grouping of about 240 airlines worldwide.

Both parties sealed the partnership in a signing ceremony on the sidelines of the Singapore Airshow Aviation Leadership Summit yesterday. A model of the aircraft was displayed at the Raffles City Convention Centre, where the summit was held.

Solar Impulse president Bertrand Piccard said the US$70 million (S$99 million) prototype aircraft will be built to carry just the pilot.

It will have a wing span of about 80m - similar to that of the Airbus A380 superjumbo - so that solar panels can be fixed to allow it to capture enough power.

Several solar-powered craft have taken to the skies in recent years, including one that flew across continental United States in several stages.

But Solar Impulse is attempting what will be the longest non-stop flight ever by such a craft.

On whether such an aircraft can be commercially viable, Mr Piccard stressed that the price of energy 'will oblige everyone (including the big plane makers) to find alternatives if they want to survive'.

But while the world is still many years away from a solar-powered jet that can carry more than 300 people, a more commercially viable option may well be a hybrid jet, he said.

Iata director-general and chief executive officer Giovanni Bisignani noted that while aviation contributed to just 2 per cent of man-made carbon emissions, the industry is bent on reducing its carbon footprint further by investing in new technology, for instance.

A solar jet is ambitious, Mr Bisignani said, but 'we are in an industry built on turning dreams into reality'.