(a) Airport layout plan. As used in this part, "airport layout plan" means the basic plan for the layout of an eligible airport that shows, as a minimum --

(1) The present boundaries of the airport and of the offsite areas that the sponsor owns or controls for airport purposes, and of their proposed additions;

(2) The location and nature of existing and proposed airport facilities (such as runways, taxiways, aprons, terminal buildings, hangars, and roads) and of their proposed modifications and extensions; and

(3) The location of existing and proposed non-aviation areas, and of their existing improvements.

All airport development under the Federal-aid Airport Program must be done in accordance with an approved airport layout plan. Each airport layout plan, and any change in it, is subject to FAA approval. The Administrator's signature on the face of an original airport layout plan, or of any change in it, indicates FAA approval. The FAA approves an airport layout plan only if the airport development is sound and meets applicable requirements.

(b) Safe, useful, and usable unit. Except as provided in paragraph (d) of this section, each advance planning and engineering proposal or airport development project must provide for the planning or development of --

(1) An airport or unit of an airport that is safe, useful, and usable; or

(2) An additional facility that increases the safety, usefulness, or usability of an airport.

(c) National defense needs. The needs of national defense are fully considered in administering the Federal-aid Airport Program. However, approval of an advance planning and engineering proposal or a project application is limited to planning or airport development necessary for civil aviation.

(d) Stage development. In any case in which airport development can be accomplished more economically under stage construction, federal funds may be programmed in advance for the development over two or more years under two or more grant agreements. In such a case, the FAA makes a tentative allocation of funds for both the current and future fiscal years, rather than allocating the entire federal share in one fiscal year. A grant agreement is made only during the fiscal year in which funds are authorized to be obligated. Advance planning and engineering grants are not made under this paragraph.