While autonomous flight is often associated with drones, a revolution in autonomy is unfolding in the stratosphere. At altitudes of about 20 km, high-altitude platform stations (HAPS) from the likes of Airbus subsidiary Aalto, Thales, and BAE Systemsâ Prismatic are targeting the largely untapped airspace between most air traffic and low-Earth-orbit (LEO) satellites. Far above the clouds and high w...