Real property, real estate (and all that grows thereon), and the right to minerals underneath and the airspace over it. it may include improvements like buildings, but not necessarily. the owner of the land may give a long-term (like 99 years) lease to another with the right to build on it. the improvement is a “leasehold” for ownership of the right to use-without ownership of-the underlying land. the right to use the air above a parcel of land is subject to height limitations by local ordinance, state or federal law.