It is true that executive agencies are located within the executive branch, generally under one of the cabinet-level departments. Therefore, they are also called as cabinet-level agencies.
With advice and consent from the US Senate, the administrative head of an executive agency is appointed by the President, and they can also be discharged by the President at any given point for any reason.
The Food and Drug Administration (FDA) and the Federal Aviation Agency (FAA) are perfect examples of an Executive agency.
