.
We see wind turbines everywhere. But in the sky?
In August 2026, China flight-tested the S4000, a helium-filled airborne wind system, at a site in the country’s northwest. The craft is about 67 metres long, 40 wide and 23 high, roughly the length of a Boeing 747. It is meant to work at up to 4,000 metres, where the wind is stronger and steadier than it is around a tower on the ground.