The sun-powered .
The two pilots alernate legs of the journey. Piccard is piloting the Dayton to Allentown trip. The plane has already traveled from San Francisco to Phoenix, Phoenix to Tulsa, and Tulsa to Dayton. New York City is the final U.S. destination. The first leg began in March 2015 in Abu Dhabi . It continued with several more legs across Asia before Borschberg completed the world's longest non-stop solo flight, a four-day, 21-hour and 52-minute excursion from Japan to Hawaii. But that record-breaking flight damaged the plane's battery. Because of the time needed to repair it and the decreasing sunlight as a result of the changing seasons, the pilots called off their attempt to complete the trip in a single year.
The plane took off again in late April from Hawaii to San Francisco. After flights across the U.S., it's scheduled to undertake two final legs over the Atlantic Ocean and the Mediterranean Sea before landing back in Abu Dhabi VIDEO here.
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FLYING ON SUN POWER
Solar Impulse 2, a solar-powered airplane that uses no fuel, is making a nearly 22,000-mile, round-the-world voyage. After previous flights from San Francisco to Phoenix, Phoenix to Tulsa, and Tulsa to Dayton, the plane will fly to Allentown, Pa., on May 25. It will make its final U.S. landing in New York City.
