Air rights mean the estate, title, interest and rights in the open space or vertical place above ground level. Any ownership of land includes the ownership of air rights, which are subject to reasonable aircraft interference. The air is not real property but airspace is real property when described in three dimensions with reference to a specific parcel of land. Air rights can be sold purchased, mortgaged, leased, or otherwise encumbered. The alienability of air rights is greatly impaired by easements of light and air.
EXAMPLES: A condominium unit, which involves the ownership of a certain specified layer of air space, and an aviation easement, which is the right granted to aircraft, when approaching an airport, to fly at a stipulated altitude over certain specific land.