Project Loon, part of Google parent Alphabet, is one of the first to exploit these countervailing winds with high-altitude balloons to provide communications in remote or disaster-hit areas. The original plan was a stream of balloons following the prevailing wind, but researchers found the balloons could stay in place by using countervailing winds at different heights. Sophisticated machine-learning algorithms change height to catch the right wind.
Project Loon gave internet access to 300,000 people in Puerto Rico after hurricane Maria destroyed infrastructure in 2017. This proved that the concept works, even though it is still at the experimental stage.
Read more at BBC