The International Air Transport (IATA) has expressed optimism that solar technology could one day play a major role in powering commercial flights after yesterday inking an alliance with a research project aiming to undertake the first round-the-world-trip by a manned solar powered airplane.

The Solar Impulse project is backed by Swiss adventurer Bertrand Piccard and is working on developing a solar powered aircraft capable of flying for over 24 hours.

The ultra light weight aircraft will have a wingspan greater that the world's largest passenger plane and researchers are confident that the solar panels on the wings will be able to generate enough energy during the day to charge lithium batteries that will allow flight to continue overnight.

Piccard said that the first test flight will be undertaken early next year with a round-the-world journey involving a series of stop overs to change pilots scheduled for 2011.

Each leg of the flight is expected to last four to five days, but the company claims improvements in solar panels and battery efficiency will ultimately allow it to carry two pilots, making non-stop round-the-world-flight a possibility.

Piccard said that the long term goal of the project was to increase the efficiency of the technology so as to carry "a few hundred passengers."

It is an ambition endorsed by the IATA, which has set the goal of developing a zero carbon commercial airliner by 2050, and this week agreed to support the Solar Impulse project by helping to resolve air traffic issues for the maiden round-the-world flight.

Quentin Browell of the IATA said that alongside fuel cells and biofuels solar energy was one of the main technologies the aviation industry was exploring as it seeks to deliver zero carbon flight.

He admitted there were major challenges to be overcome before solar panels c ould play a role on commercial airliners, noting that the Solar Impulse plane will be the same size as an Airbus A380 but will only carry one person.

However, he added that improvements in solar cells, batteries and the lightweight fuselages meant there was a possibility solar could play a significant role in aircraft design over the coming decades.

"Solar may end up supporting auxiliary functions or it may contribute to the engines," he said, adding that the goal of zero carbon flight by 2050 is not as outlandish as it first appears. "You have to remember that it was less than 50 years between the Wright Brothers' first flight and jet engines and transatlantic airliners, so this scale of change is definitely possible," he observed.