Banjo Music courtesy of BanjoHangOut Last the numbers don’t work in order to receive 24 hour “sunshine” a propeller device would have to fly in the troposphere which begins 18 miles above Earth.  70,000 feet equates to just over 13 miles.  A solar  powered device might work well up until September 21st but after that nights will be longer than days. Even at 70,000 ft. If these drones did log 67 Continous days of flight it was obviously done as a relay no single unit could manage it. The numbers just don’t work!