Air rights involve the use of airspace above a piece of land and are classified as a landowner appurtenant right or interest.
Be aware that government regulations may limit the altitude and use of airspace associated with air rights. Likewise, if a landowner’s use of air rights negatively impact other landowners, they may incur damages and have cause for legal action.
Downtown Denver’s iconic example of air rights involves the Holy Ghost Catholic Church, which owns the land it is built on and its beautiful stone building, but sold the air rights to a skyscraper developer. The result is an interesting marriage of traditional stone and modern glass designs.