[Earw0rm]

Ultra-long endurance drones and balloons for remote sensing are a thing, but this kind of approach doesn't scale well to higher cargo payloads.

[grumpy-de-sre]

Most of the stratospheric approaches I've seen aren't so much about exploiting low altitude weather phenomenon but rather flying above it. Which of course is exactly what you want for long term remote sensing.

I'm thinking systems that mostly exploit thermals and updrafts, engaging in a kind of bird like automated soaring.

https://www.youtube.com/watch?v=H-zvzOC8dzA