I did find about 4 sources that use the term, but it is qualified with 'air' or 'aerial' in most (3) of them. One merely says
A no-fly zone is a de facto aerial occupation of sovereign airspace.
But alas doesn't talk much about any implications of the 'occupation' (term), despite being a lengthy paper (57 pages), except in a footnote:
Petersen explores the idea of a no-fly zone as an occupation. It should be noted, however, that the concept of aerial occupation is not a legal one. In
traditional humanitarian law, occupation is a term of art for physical control by one belligerent over land territory of another (or of a State occupied against its will, but without resistance).
When an occupation occurs, rights and duties arise as between the occupying power and individuals located in the occupied area. An aerial occupation, by contrast, is simply a de facto, vice de jure, status in which limits are placed on a State's use of its own airspace. Traditional occupation law is found in Geneva Convention Relative to the Protection of Civilian Persons [...]
Interestingly, Petersen (1996) is quite bold in his claims:
The historical analysis conducted in this research shows that the use of no fly zones accomplishes both components of occupation, holding and controlling.
Therefore, this thesis concludes that the use of no-fly zones accomplishes the
strategic goals of occupation.
Another source (J.M. Jouas) is more reserved and says:
A no-fly zone is viewed by some as an "air occupation," and by others as an "air
In the former, the legal implications ofthe term "occupation," and the
inherent responsibilities of an occupying nation, raise a difficult issue that should relegate
the use ofthe term to all but the most general of descriptions or discourses. In the latter,
conventional and moral implications ofthe term "intervention" are both at issue. [...]
These considerations notwithstanding,
the commonly understood definitions of "occupation" and "intervention" appropriately
describe the function of a no-fly zone.
Air "occupation" is a limited objective, and a qualified concept; airpower doesn't
occupy a nation, nor does it occupy territory --it occupies airspace, and thus controls
territory. Within this realm airpower can restrict the transit of aircraft to varying degrees,
conduct surveillance, airdrop supplies, or simply contain an opponent's forces while
constraining his will. It can deny a nation's aerial sovereignty, and have a devastating
effect on its political, economic, military, and human condition. It can affect
transportation, telecommunication, television, and radio - all without the destructive use
of force. If necessary, a no-fly zone can escalate beyond observation or patrol, and
provide the means to conduct offensive bombing operations. [...] Limited objectives may, only
require a limited use of force, but a limited use of force can only achieve limited
The phrase "it occupies airspace, and thus controls territory" isn't alas detailed much than the above.
Anyhow, the divergence in views (between Petersen and Jouas) is that the former contends that air power can also 'hold' an area, not just 'control' it. This is quite an YMMV, as you'll see below.
Petersen himself quotes more opposing views, which deny that the no-fly zones in Iraq even achieved 'control':
The curriculum at the Air Command and Staff College includes
several courses on war termination. Occupation is discussed as well as
the term "Air Occupation." One of the required readings is the article
"Air Power as a Tool of Foreign Policy: Air Occupation" by Major Gary
Cox. Five conflicts are used as examples of air occupation. His
definition of air occupation is as follows:
The use of air and space power in the intrusive control of specified
territory, or territorial activities, of an adversarial nation or
group for a specified period of time.
He states that this is the ideal and must be qualified by three
characteristics. First, air superiority must be achieved. Second,
there must be a desire to limit or eliminate the use of ground forces.
Third, air occupation combines the elements of intelligence,
surveillance, presence, and deterrence.
Major Cox asserts that the no-fly zones in Iraq are not air
occupations, because they do not control activity on the ground.
A point of contention is whether merely carrying air-to-ground munitions but not using them much counts as exercising (what degree) of ground control:
The forces in place for these no-fly zones are the very same type used in what Cox terms "Air Dominance" in the Gulf War. In fact the air-to-ground
capable aircraft still carry munitions similar to their wartime loads.
The fact that they have not often been used to influence ground
operations is a political decision, not due to a lack of capability.
OTOH, Petersen says that the British, in the aftermath of WW1 more clearly exercised the control aspect because they were willing to much more often bomb the unruly tribes in their colonies (Somaliland etc.)
As for the 'hold' part, this is the most nebulous. Petersen argues that at least in Northern Iraq that happened, because the Kurds established a de facto quasi-state there. OTOH, he elides any discussion on the relationship between the [Iraqi] Kurds and Washington, i.e. whether they could be considered US proxies or something like that. As for the Iraqi South, he somewhat more vaguely claims that the various groups there had contradictory goals, some democratic and some Islamist. He doesn't discuss at all their level of organization or relationship with the US. So, ultimately his idea of 'hold' seems to be that the Iraqi government (Saddam's) wasn't holding those areas, but someone else was. One has to give this old (1996) paper the benefit of not knowing later events like how Saddam crushed the 1999 rebelion even under the [Southern] no-fly zone.
So, I guess there's quite a spectrum of opinions on this, but seeing them (no fly zones) as nearly the same thing as [unqualified] occupation is a rather tenuous endeavor, not attempted by many. The more middle ground seems to be that no-fly zones exercise some degree of control on some events on the ground. But this seems to be a function (ultimately) on the willingness to use air-to-ground munitions.