Airport projects involve a unique eminent domain issue that you do not see with other projects. For a new airport, the government will need land like any other project. However, for a new airport or airport expansion, the government will need to acquire air rights around airport. An avigation or aviation easement is an easement or right of overflight in the airspace above or in the vicinity of a particular property. The rights acquired also includes the right to create such noise or other effects as may result from the lawful operation of aircraft in such airspace and the right to remove any obstructions to such overflight.
The are several damage issues in airport projects. First, concerns the highest and best use of the property with the new aviation easement in place. Where before the easement, you can develop the property without restriction; after the easement, there may be height, intensity or density restrictions limiting how tall buildings can be or even how many homes can be built in the easement area. Other issues could simply damage the existing development by noise or even as simple as taking a pond (because waterfowl could impact flights) that enhanced the value of the property. The attorneys at Biersdorf have handled many airport project cases and are familiar with the unique problems they cause property owners.
Here is the FAA overview for land acquisitions for airports.