Air Defense Identification Zone - United States

United States

The United States formally defines an ADIZ in the Code of Federal Regulations: 14 CFR Part 99. It extends approximately 200 miles off the national coastlines. Furthermore 14 CFR Part 99.49 states "All airspace of the United States is designated as Defense Area", in which by definition the control of aircraft is required for reasons of national security. Therefore the ADIZ forms a transition zone in which aircraft come under positive identification and control by air traffic and defense authorities. 14 C.F.R. 99.11a states "No person may operate an aircraft into, within, or from a departure point within an ADIZ, unless the person files, activates, and closes a flight plan with the appropriate aeronautical facility, or is otherwise authorized by air traffic control", which appears to claim authority over all aircraft in the external U.S. ADIZ regardless of destination.

However, the U.S. Navy's Commander's Handbook on the Law of Naval Operations states the ADIZ applies only to commercial aircraft intending to enter U.S. sovereign airspace, with a basis in international law of "the right of a nation to establish reasonable conditions of entry into its territory". The manual specifically instructs U.S. military aircraft to ignore the ADIZ of other states when operating in coastal areas:

The United States does not recognize the right of a coastal nation to apply its ADIZ procedures to foreign aircraft not intending to enter national airspace nor does the United States apply its ADIZ procedures to foreign aircraft not intending to enter U.S. airspace. Accordingly, U.S. military aircraft not intending to enter national airspace should not identify themselves or otherwise comply with ADIZ procedures established by other nations, unless the United States has specifically agreed to do so.

Meanwhile in actual practice the U.S. does attempt to apply its external ADIZ to military aircraft which pass through its extended ADIZ without intending to enter U.S. sovereign territory . A U.S. Air Force university dissertation states:

These regulations do not pertain to military aircraft, but to enter US airspace, without inducing the scrambling of fighter interceptors, these rules must be complied with and followed. The US does not claim sovereignty over these zones per se, but does closely monitor and request information of all objects entering the zone.