An easement is the right to use or enter onto someone else’s land for a specific purpose. For example, a utility company may have an easement to bury water mains or access utility lines. Easements may also be negative, such a light and air easement, which protects a buildings view by preventing neighboring properties from building any structure that would obstruct it. In some cases, the concept of “using” the land may be defined in a fairly abstract way, such as aviation easements, which may grant the right for low-flying planes to occupy the air above a property and to cause noise or dust.
Easements are very common in New York City, and the terms vary on a case-by-case basis. Any concerns should be addressed with an experienced lawyer.
An example of an air easement in use (“The Giant Tetris Game on Third Avenue”, scoutingny.com, 6/23/2013)