Solar Impulse 2 (Si2) has started its first flight from Abu Dhabi this morning in a record-breaking attempt to travel across the world using zero fuel.

The single-seater experimental solar aircraft with pilot André Borschberg onboard is heading to Muscat in Oman, as part of the 35,000km journey in 25 flight days over five months.

Solar Impulse founders and Swiss pilots André Borschberg and Bertrand Piccard are managing the solar-powered flight.

The aircraft will enter Omanian aerial space at an altitude of 3,600m and will head to Muscat reaching an altitude of approximately 5,800m.

In Muscat, Piccard will take over the flight and the aircraft will be prepared to cross the first water body, the Arabian Sea.

Si2 will have 12 scheduled stops, including Muscat, Oman, Ahmedabad and Varanasi, India, Mandalay, Myanmar, and Chongqing and Nanjing, China.

The aircraft will travel through the Pacific Ocean via Hawaii and fly across the US with three stopovers, including Phoenix, the Midwest, and New York. It will cross the Atlantic Ocean and make a stop in Southern Europe or North Africa before landing in Abu Dhabi.

Mr Piccard and Mr Borschberg said: "We are very ambitious in our goal, but modest given the magnitude of the challenge.

"This is an attempt, and only time will tell if we can overcome the numerous weather, technical, human and administrative issues."

The upgraded version of the solar-powered prototype Solar Impulse 1, Si2, has a wingspan of 72m and weighs 2.3t. It is equipped with 17,000 solar cells, which convert sunlight into electricity.