zone theory

In the law of trespass as it relates to flights over one's land, the theory is that a property owner has a lower zone of effective possession which should not be invaded by the government or others, but flights in the zone above that are permissible. Traditionally, property owners owned all to the middle of the earth and up to the far reaches of the heavens. Without the zone theory, every aircraft in the skies would be trespassing on someone's property.