On 9 March 2015, Piccard and Borschberg began to circumnavigate the globe with Solar Impulse 2, departing from Abu Dhabi in the United Arab Emirates.

[17] It stopped in Egypt before returning to Abu Dhabi on 26 July 2016, more than 16 months after it had left (506 days), completing the approximately 42,000 km (26,000 mi) first circumnavigation of the Earth by a piloted fixed-wing aircraft using only solar power.

[18][19] In 2019, the Solar Impulse 2 was sold to Skydweller Aero, a US-Spanish company using the airframe to develop autonomous unmanned aerial vehicles capable of perpetual flight.

[20] It plans to use the aircraft for research and development and flight testing, after which the Solar Impulse 2 will be returned for permanent display at the Swiss Museum of Transport.

Bertrand Piccard initiated the Solar Impulse project in November 2003 after undertaking a feasibility study in partnership with the École Polytechnique Fédérale de Lausanne (EPFL).

[34] In addition to the charge stored in its batteries, the aircraft uses the potential energy of height gained during the day to power its night flights.

The aim was not to get high but to land on the same runway at a speed to test its controllability and get a first feeling of its flying characteristics ... the craft behaved just as the engineers had hoped.

[48] At the time, the flight was the longest and highest ever flown by a manned solar-powered aircraft; these records were officially recognized by the Fédération Aéronautique Internationale (FAI) in October 2010.

"[52][53] A second international flight to the Paris Air Show was attempted on 12 June 2011, but the plane turned back and returned to Brussels because of adverse weather conditions.

[56] On 3 May 2013, the plane began its cross-US flight with a journey from Moffett Field in Mountain View, California, to Phoenix Goodyear Airport in Arizona.

[59] On 6 July 2013, following a lengthy layover in Washington, Solar Impulse completed its cross-country journey, landing at New York City's JFK International Airport at 23:09 EDT.

[8][60] The landing occurred three hours earlier than originally intended, because a planned flyby of the Statue of Liberty was cancelled as a result of damage to the covering on the left wing.

[7][61] The aircraft's second leg of its trip on 23 May to Dallas-Fort Worth covered 1,541 kilometres (958 mi) and set several new world distance records in solar aviation.

Source:[63] In March 2015, the plane was transported by truck to Paris to be part of the permanent exhibition at Cité des Sciences et de l'Industrie.

[68] It features a non-pressurized cockpit 3.8 cubic metres (130 cu ft) in size[69] and advanced avionics, including limited functionality of an autopilot that allows the pilot to sleep for up to 20 minutes at a time,[70] enabling multi-day transcontinental and trans-oceanic flights.

[73] The aircraft was delivered to Masdar City in Abu Dhabi for the World Future Energy Summit in late January 2015,[74] and it began the journey from Al Bateen Executive Airport on 9 March 2015.

[10][76] A mission control centre for the circumnavigation was established in Monaco, using satellite links to gather real-time flight telemetry and remain in constant contact with the aircraft and the support team.

[79] For most of its time airborne, Solar Impulse 2 cruised at a ground speed of between 50 and 100 kilometres per hour (31 and 62 mph), usually at the slower end of that range at night to save power.

[83] With Borschberg in the cockpit, it reached Hawaii on 3 July, setting new records for the world's longest solar-powered flight both by time (117 hours, 52 minutes) and distance (7,212 km; 4,481 mi).

[15] During that flight, Piccard, via a live videolink, spoke with Ban Ki-moon and Doris Leuthard before the General Assembly of the United Nations, from the cockpit of Solar Impulse 2, commenting on that day's historic signing of the Paris Agreement and discussing how using clean technologies can create jobs and fight global warming.

[90] Additional legs of the flight were added in the US as Solar Impulse 2 flew to Phoenix, Arizona,[91][92] Tulsa, Oklahoma,[93] Dayton, Ohio,[94] Lehigh Valley, Pennsylvania[95] and New York City, arriving there on 11 June 2016.

[19] In September 2019 the Solar Impulse 2 aircraft was sold to Skydweller Aero, a Spanish-American company that is developing autonomous unmanned aerial vehicles capable of continuous flight and "carrying radar, electronic optics, telecommunications devices, telephone listening and interception systems".