The Swiss-made "Solar Impulse 2" airplane has landed in Tulsa, Oklahoma, after an 18-hour journey.

It took off from Phoenix Goodyear Airport in Arizona early Thursday.  This was the latest leg of its round-the-world journey using only the power of the sun. 

Last month, Solar Impulse 2 flew across the Pacific, from Japan to Hawaii and then to California, without a drop of fuel. CCTV's Jessica Stone caught up with its pilot to find out how his invention is changing the conversation about what solar can power.

With a wingspan as big as a jumbo jet, but the weight of a sport utility vehicle, Solar Impulse 2 is an aircraft like no other.

"Solar Impulse has no fuel. It flies only with the sun, but it's the beginning of something, you know. It's really experimental. It's a door slightly open to the future, pushing the technologies to the extreme ultimate applications," said Bertrand Piccard, Solar Impulse 2 Founder, Pilot.

"This is Solar Impulse. It's the first plane flying around the world just on solar energy."

It took 14 years for Bertrand Piccard - a Swiss medical doctor and explorer - to help design this plane and now pilot it. A journey that began in Abu Dhabi in March 2015 has taken him and his co-pilot, Andre Borschberg, from the Arabian Peninsula through Myanmar to China, where it remained for two months.

"The Chinese are very interested by clean technologies. They know it's the future, and China is moving very fast in the direction of clean technologies in order to have cleaner air. And they have a really smart way to move ahead, investing a lot in solar and wind," Bertrand Piccard said.

After an emergency stop in Japan, and a winter-layover in Hawaii to replace the batteries, Piccard spent three straight days and nights in this cockpit to cross the Pacific Ocean from Hawaii to California, arriving in late April.

During his journey, he addressed the UN where leaders from more than 175 countries signed the 2015 Paris climate accord.

The plane is now on the eleventh stage of its voyage-heading east across the US to New York, before crossing the Atlantic.

It'll be more than year before Solar Impulse 2 completes its journey.

"It's not about speed. It's really about slow and steady. It will arrive when it arrives," said Elke Neumann, Solar Impulse 2 spokesperson.

And it's a team effort-with 60 people on the ground, and another 70 in mission control located on Monaco. They help the pilot navigate this light-weight aircraft around wind and heavy rain.

"To show that with clean technologies, you can achieve things that people consider impossible. like flying day and night without fuel. This is the value of clean tech and what I want to push is really the implementation of energy efficient technologies in everyday life."

By now, it's a message that has nearly circled the globe. Solar Impulse is due to arrive back in Abu Dhabi this July.