Follow up question, why aerial drones? Couldn't crawler drones work and avoid FAA regulations? Though obviously would be limited in speed and where lines have been damaged, though perhaps they could be managed to go around the damage via remote control.
Crawler drones are not a bad idea! They're just a bit slow and limiting. Also doesn't drive our long term plan (can't leave power lines)
It's also mechanically complex and there's many line & pole types that make it challenging to build for.
When we let go of distribution line charging, we considered this idea. Off some rough calcs we thought there would be lines that we'd get 'stuck' on so that was hard to overcome...
Not all lines are on nice level land. Transmission lines go through some rugged terrain. I've seen some distribution lines that are in pretty rugged areas as well. They also mentioned the top down view was advantageous compared to a ground pounder's view, so a crawler would loose that view as well.
Delivery drones are leaving line of sight and yet they are operating. The Walmart near me started delivery late last year, and they are buzzing my area many times a day. I'd hope with enough testing these guys can work with the FAA to get certified to remove this limit.