This subsection is without prejudice to the rights of proclaiming “Air Defence Identification Zones” (ADIZ) or “Flight Information Regions” (FIR). These rights are enjoyed by every State, in times both of peace and armed conflict. ADIZs are zones established in international airspace adjacent to national airspace by which States establish reasonable conditions of entry into their territory. FIR is an aviation term used to describe airspace with specific dimensions, in which a flight information service and an alerting service are provided. Oceanic airspace is divided into Oceanic Information Regions and delegated to controlling authorities bordering that region. The division of authorities is done by international agreement through ICAO.

The object and purpose of this Rule is to emphasize this belligerent right and to distinguish no-fly zones from “exclusion zones”. For the purposes of this Manual, no-fly zones cannot be established in international airspace.

A Belligerent Party establishing and enforcing a no-fly zone is under an obligation to publicize the details laid down in Rule 109 to “all concerned”, i.e. to civil aviation — own, enemy or neutral — if the zone will have an impact on such aviation. There is no obligation to inform enemy military aircraft (which are military objectives by nature). As to the means of communicating the details (e.g., by NOTAM), see paragraph 2 of the Commentary on Rule 107 (c).

1. Sections D and G deal, respectively, with attacks and precautions in attack.
2. Rule 110 reflects that unauthorized presence in a no-fly zone may be considered an indicator of hostile intent, but in no way implies that mere presence within the zone is sufficient to warrant attack. In other words, such presence by itself does not trigger the application of the criterion of “location” to render it a military objective under Rule 22 (b).
3. As emphasized in the UK Manual, “attacks on ostensibly civil aircraft ought only to be carried out as a last resort when there is reason to believe that it is itself deployed on an attack”.^[613]
4. Rule 110 does not authorize automatic engagement or a “free-fire zone”. As in “exclusion zones”, the principles of target discrimination (Sections D and E) and the Rules of Section G still apply.

613. Para. 12.58.2. of the UK Manual: “The presumption, in Additional Protocol I, of civilian status in cases of doubt does not, strictly speaking, apply in air-to-air combat [see Art. 49 (4) of AP/I] Nevertheless, attacks on ostensibly civil aircraft should only be carried out as a last resort when there is reason to believe that it is itself deployed on an attack. An example might be when, during an armed conflict, an exclusion zone has been established around the United Kingdom and an apparently civilian airliner enters the zone on a course set for a major city, all required notification and other procedures to establish the zone have been meticulously completed, and all attempts to communicate with the aircraft, including buzzing, have failed or been ignored.”