Interesting question. From a quick trawl of wikipedia (I promise I don't do all my legal research on there
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Air rights - Wikipedia, the free encyclopedia
Originally you did have rights over everything above and below your property, but this has been watered down (since the advent of the aircraft) to only that airspace which you can reasonably make use of. Therefore if I fly an aircraft at 10,000 feet above your property, you would have no ability to stop me from doing so and I wouldn't be 'trespassing' in the ordinary meaning of the word.
I imagine the position is similar in the UK and other common law jurisdictions.
Interesting point made in the article that the 500 feet rule (the US version looks very similar to the UK version) appears to trump 'air rights', by allowing you to fly as low as you wish, so long as you don't fly within 500 feet of any person or structure, unless you are taking off or landing.
Ever noticed how utility lines never pass over a house? To do so would require an easement which requires the owner's permission. This applies to anything intended to be built or carried over the owner's land, that could reasonably cause obstruction/harm/cause an eyesore, etc.
Yes but this is getting into the territory of planning permission, covenants, easements etc. i.e. rights and restrictions over the land rather than airspace. It's unlikely that utility wires would be high enough off the ground to be outside the airspace you could reasonably make use of.