Just as nations are entitled to control the airspace within their borders, individual land owners are entitled to controlling the airspace above their property. The issue over air rights becomes apparent in condensed urban centers where space is at a premium.
Use In Building Construction
Air rights are an important consideration of construction in urban neighborhoods. In many cases such areas were home to previous industrial activity comprising a mix of low-rise rental blocks, industrial workshops and even single unit housing. As cities expand, these areas usually become gentrified into large density high rises.  To protect the property rights of existing owners, these rights can be exercised to prevent developers from expanding beyond their allotted footprint.
Transfer of air rights
The transfer of air rights can be a lucrative enterprise, especially in highly condensed cities such as New York, Chicago or Vancouver where existing real estate is scarce and expensive.  Historic Grand City Terminal in New York city became one of the first properties to market these rights when a tower was proposed on the existing site. While public outcry prevented this project from going through, other owners, in particular churches have capitalized on their urban locations. Allowing buildings to expand overhead beyond their titled property for a nominal charge. Cities also have marketed air rights that have enabled buildings to be constructed over rail lines, highways and public transit routes.
Common Law Air Rights
Property owners are protected by air rights in such instances 
- Owners are allowed to build above the surface of their property
- Owners are allowed to restrict others from building above the surface of their property
- Owners are entitled to fresh and unpolluted air
- Owners are entitled to unobstructed sunlight
- Owners can remove tree limbs that enter their air space
- Owners can require the removal of eavestroughs or other encroachments that may exist above the surface of their property