A while back, I was thinking about how to to make an ultra-long range drone. Like something I could send off on a mission, and expect it to come back on it's own later on. One of the ideas, if it were battery powered, was to instruct it to land on or near power lines. That would have been a nightmare to figure out though.
To be stealthy, it would need to fly around 5K to 10K feet. It wouldn't be able to approach ground level, except in uninhabited areas. There's no way you'd get a map of all the high tension power lines in the world, and I don't know of any method of detecting them miles away. Well, other than Hollywood magic methods, which unfortunately don't translate well to the real world. :)
To land on power lines or on the connecting towers, it would have to hover, which is battery expensive. Automatically picking an arbitrary landing spot isn't exactly easy. Once you're parked close to the power lines (like on them, or on the towers) inductive loops could handle farming electricity without human intervention or needing to deploy charging mats.
In the end, I gave up on the idea. I don't really have a reason to make one. If I did, and it worked, I'd have all the lovely three-letter-agencies knocking on my door to have a chat over a nice cup of tea.
Maybe "nice" would be optional in their opinion, and cup of tea would be room temp water in an interrogation room. Either way.