I think the theory of the drones being sent by us to check powerlines is illogical. If they were our's I don't think we would be using advanced technology (especially Alien) for something as mundane as checking powerlines. Putting billion dollar devices to do the work that some poor shlep being paid a minimum wage could do does not gel with me.
I think they may be attracted to powerlines for some reason. Or maybe the fact that there are telephone poles and powerlines all over the place just simply means the odds are they are going to wind up in some of the shots.
Obviously they don't look like they carry anything so I would imagine they are designed to do something such as map, monitor, remove or place something. I think mapping and monitoring make more sense.
Maybe they make crop circles and we just can't see them 
One sighting I had was in the Fall/Winter of 1995 when a sudden nighttime snowstorm hit the area. I was driving on 494 in low visibility when blinding lights lit the whole sky for five seconds, alternating reddish, yellowish and greenish every second. I say the color was "ish" because the intensity was so bright that the brilliance seemed to dominate the color.
I could not see the object with these lights, but it was located to the east side of the highway, just over 200,00 volt transmission lines.
I was going to go UFO hunting after this sighting as there was a large athletic field in the same area and I thought it might have landed. My co-worker who I was going to give a ride thought she wanted no part in any such a hunt. HUMPH, I wonder if it did land, or whether it was just topping off its power supply.
