Another air record has been (unofficially) broken as a prop-driven solar/electric aircraft reached the highest altitude yet for its type. On August 12, 2025, a modified Elektra One reached 31,237 feet (9,521 m) in the skies over Switzerland.
Taking off from Sion Airport with SolarStratos founder Raphaël Domjan at the controls, the aircraft registered as HB-SXA conducted a five-hour, nine-minute flight completely under solar power, with a two-hour ascent and a three-hour descent over the Valais Alps .
Weighing a mere 992 lb (450 kg), the aircraft had wings spanning 81.4 ft (24.8 m), which were covered with solar panels that powered a 43-bhp electric motor reportedly operating at 90% efficiency. A 20-kWh lithium-ion battery provided backup, giving the aircraft an estimated endurance of 24 hours.
SolarsStratos
That may not seem like a lot of performance for not much power, but the HB-SXA is essentially a powered glider designed to take advantage of thermals and other updrafts to gain and maintain altitude. It’s part of the SolarStratos project, which is a Swiss aeronautical initiative aimed at demonstrating the potential of solar and electric power for high-altitude, long-duration flight, with the ultimate goal being to soar into the stratosphere at 82,000 ft (25,000 m).
To do this, the aircraft has been modified to be ultralight, including leaving the cockpit unpressurized, so Domjan was clad in a specially made pressure suit for protection from both the lack of air and the extreme cold.
Though SolarStratos claims to have broken the previous altitude record of 30,298 ft (9235 m) set by Solar Impulse 3 on July 9, 2010, it’s still unofficial pending confirmation by the Fédération Aéronautique Internationale (FAI).
Source: SolarStratos
