Critical Infrastructure Sectors
There are 16 critical infrastructure sectors whose assets, systems, and networks, whether physical or virtual, are considered so vital to the United States that their incapacitation or destruction would have a debilitating effect on security, national economic security, national public health or safety, or any combination thereof. Presidential Policy Directive 21 (PPD-21): Critical Infrastructure Security and Resilience advances a national policy to strengthen and maintain secure, functioning and resilient critical infrastructure. This directive supersedes Homeland Security Presidential Directive 7.

 

Aviation is Part of Our Critical Infrastructure Sectors
Aviation includes aircraft, air traffic control systems, and about 19,700 airports, heliports and landing strips. Approximately 500 provide commercial aviation services at civil and joint-use military airports, heliports, and sea plane bases.  In addition, the aviation mode includes commercial and recreational aircraft (manned and unmanned) and a wide-variety of support services, such as aircraft repair stations, fueling facilities, navigation aids, and flight schools. Source Link