From March 2015 to July 2016, the Solar Impulse circumnavigated the globe. This aircraft, powered solely by solar energy, travelled some 43,041km in 17 stages (to swap pilots and promote the project) and 558 cumulative flying hours. According to one of the pilots, it was more of a test of human endurance than a technical challenge. Indeed, the unpressurised single-seat cabin offered no protection against significant temperature variations (+/-55 degrees). It’s hoped that future flights could take additional passengers and operate non-stop.