Lenarčič, who had to postpone the start of the feat several times since 3 January because of different problems, is flying a Virus SW 914, a 290-kilo plane built by Slovenian company Pipistrel.

He will fly westwards, flying over the Equator six times as well as crossing the Antarctic, Mt Everest, 120 national parks and three oceans.

The adventure is expected to last between two to three months, while the total distance covered is estimated at 100,000 kilometres. The cost of the project is estimated at EUR 2m.

The flight is environmentally-oriented, with the SW 914 boasting the lowest fuel consumption on record in its category. Lenarčič will be able to fly up to 300 km/h, and cover a distance of 4,000 kilometres with 350 litres of fuel.

Lenarčič, who is a also photographer, will be taking photos of the earth, but also conducting different kinds of research. He will for instance be the first to conduct black carbon measurements in the atmosphere.

The Slovenian adventurer was the first person to circle the globe in an ultralight airplane without a copilot or additional air support in 2004.

Flying the Pipistrel Sinus 912 UL aircraft, which weighs a mere 284 kilo, Lenarčič also set a new speed record in the category of airplanes under 500 kilo then.