The Solar Impulse 2 has completed the next leg of its history-making journey on 2 May in Arizona, marking the midway stage in its attempt to circle the globe after a relatively short 16-hour flight from northern California.

The spindly, single-seat experimental solar-powered aircraft arrived in Phoenix at 8.55pm local time. The lengthy duration of the flight, which a normal airline flight would make in just two hours, stems from a cruising speed more akin to that of a car, requiring pilots to practise meditation and hypnosis in training to stay alert for long hours.

Occupying the plane's tiny cockpit for the trip was Swiss aviator Andre Borschberg, a co-founder of the project. He and fellow pilot Bertrand Piccard, also of Switzerland, will take turns at the controls for each segment of what they hope will be the first round-the-world solar-powered flight.

After landing in Phoenix Goodyear Airport, Borschberg said: "I had a lot of tailwind today so I was going too fast, so to slow down I started to fly backwards, I was flying not as fast as the wind so the wind was pushing me backwards here to Goodyear because it was important to land after sunset when the air is a bit less turbulent. So you have to adapt, you know, and find new strategies. But the great advantage of this airplane is that you don't have to land, I mean you don't have to refuel, so you can stay in the air almost forever."

Borschberg was the pilot for the Japan-to-Hawaii trip over the Pacific last July, during which he remained airborne for nearly 118 hours. That shattered the 76-hour world duration record for a non-stop, solo flight set in 2006 by the late American adventurer Steve Fossett in his Virgin Atlantic Global Flyer. It also set new duration and distance records for solar-powered flight.

The Swiss team hopes eventually to complete its circumnavigation in Abu Dhabi, where its journey began in March 2015 as part of campaign to bolster support for clean energy technologies. In a precursor to their globe-circling quest, the two men completed a multi-flight crossing of the United States with an earlier version of the solar plane in 2013.