It took off from Seville on Monday.
After a photo op with the Great Pyramids, the Solar Impulse 2 airplane touched down in Egypt for the last layover in its 16-month, round-the-world odyssey.
With its limitation on passengers and slow pace of flight, Solar Impulse 2 might not be the future of passenger aviation, but it has succeeded in demonstrating that solar power alone is capable of supporting such an impressive flight. The two men have been taking turns piloting the aircraft.
"We have to work through corridors - we have to go around areas where the [air] traffic is intense", he told FoxNews.com.
Picard, who had arrived early to greet the aircraft, told reporters that flying Solar Impulse 2 showed what new technologies can do. As a result, Solar Impulse was unable to fly between July 2015 and April 2016.
The plane has more than 17,000 solar cells built on its wings and cruises at a speed of about 70 kilometers per hour (43 mph) at a speed comparable to a vehicle. Consisting of two solar panels, two batteries with up to two days' storage capacity, and lighting units, the technology powers private homes, mosques, clinics, schools and community buildings.
Swiss pilot André Borschberg was at the controls for the last time as the solar powered aircraft completed the flight from Seville, Spain, in 48 hours and 50 minutes.
Piccard and Borschberg came up with the idea and raised $170 million to support the effort - partly to take on an epic adventure, like Piccard's round-the-world balloon flight in 1999, but mostly to draw attention to clean technologies.
For the longest uninterrupted flight, the solar airplane holds the absolute record among all kinds of airplanes. It completed the first half of its circumnavigation of the globe late last summer, after breaking multiple records on a 7,212km trans-Pacific flight from Japan to Hawaii.