Editing Homestead principle (section)

== In law ==
There are two different legal systems from which land ownership, and its scope, derive: [[Common law]] and [[statute law]]. A frequent issue of contention in both cases is the ownership of resources passing across property, such as streams or rivers, to which others downstream may assert property / water rights, and underground resources, such as subterranean water and minerals.

For limits to ownership ''above'' land, an old principle in the law is ''[[ad coelum]]'', meaning that property rights extend "to the sky" (and below the earth). In the past, rights to "the sky" have been unenforcable – birds need take little notice of humans' overhead property rights – but with modern technology extending human reach, the idea of ''[[ad coelum]]'' rights may change.{{efn|
name=hight-limits-note|
Some jurisdictions establish height limits to trespass, for example low-flying aircraft may cross over property, but must remain above a certain height limit (often above 500&nbsp;feet<ref name=CornellLaw-min-alt-14CFR§91.119/>). In 1946 the U.S. the [[United States Supreme Court|Supreme Court]] established a height-limit to property rights when it ruled in ''[[United States v. Causby]]'' (in the context of [[air traffic]]) that a landowner's exclusive use of private property ends at an altitude of 365&nbsp;feet {{nowrap|({{sfrac|111|1|4}}[[metre|m]])}} above the land surface.<ref name=SCotUS-1946-328-US-256-266/> In their ruling, the justices renounced the principle of ''[[ad coelum]]'' as manifestly unworkable in modern practice.
:
[[FAA]] and [[FCC]] regulations require tall buildings and tall antennas (typically taller than 50&nbsp;feet) to be clearly marked with warning lights, hence at that height landowners' free use of their property (say, to loft a [[tethered balloon]]) becomes encumbered, although only slightly. Note however, that the regulations do not prevent use of the property to build tall structures ''per se''; they merely require that tall structures, when built, must be marked so that they are clearly visible at all times. Above some height any tall structure must be registered with the [[FAA]], with narrow antenna towers being of particular concern, and having lower altitude limits, since they may on occasion be more difficult for pilots to see than tall buildings.
:
The only case where tall structures are expressly forbidden to property owners is when slender towers are tall enough to cross a property line, should they fall (hence possible and eventually likely trespass by the fallen tower on a neighbor's property) or if the structure impinges on an existing [[air traffic]] [[Right-of-way (property access)|right of way]], such as the approach path to an [[airport]]. In that special case, the right of way itself constitutes an established property right to the airspace, which belongs to the airport, even if it extends beyond the airport property-line.
}}{{efn|
For example, with ''[[ad coelum]]'' rights to the sky over one's property, the presence of a low-flying{{efn|name=hight-limits-note}} [[drone aircraft|drone]] overhead constitutes [[trespass to land|trespass]].{{efn|
In fact, in the absence of exceptional authority created by [[statute]], the [[drone aircraft|drone]] is illegal [[trespass to land|property trespass]] even when it belongs to law enforcement – say a [[surveillance drone]] – if the law enforcement agents who launched the [[drone aircraft|drone]] have no [[search warrant]], or they do have a [[search warrant|warrant]], but have failed to present it to the property owner or resident.
}}
Since there is no complicating issue of threatening a human life, only some person's possession, it would appear that any landowner has a free and clear right to shoot down a [[drone aircraft|drone]] intruding over the property, just as he or she would have in the case of an intruding nuisance [[dog]]. In either case, the [[drone aircraft|drone]] owner or the [[dog]] owner may be intensely upset by the loss of property or the companion animal, but would have no moral grounds nor legal recourse, due to the drone or dog's violation of the landowner's [[property right]]. This is well established in both [[common law]] and in some [[statute law]] in the case of a [[trespass]]ing [[dog]], but not so in the case of the new technology – the intruding [[drone aircraft]] – where neither [[statute]] nor [[common law]] has had time to sort out most of the issues involved, in most places.
}}

=== Common law ===
[[File:Earth-crust-cutaway-english.svg|thumb|Under the [[ad coelum]] doctrine land ownership extends in a [[Cone (geometry)|cone]] from the [[Inner core|Earth's core]] up to the [[exosphere]]]]
[[Common law]] provides the ''[[ad coelum]]'' ("to the sky") [[Legal doctrine|doctrine]] by which [[landowner]]s own everything below and above the land, up to the sky and below the earth to its core, with the exception of volatile minerals such as [[natural gas]]. The rules governing what constitutes [[homesteading]] were not specified by common law but by the local [[statutory law]]. Common law also recognizes the concept of [[adverse possession]] ("squatters' rights").<ref name=West'sEncAmLaw-2ed-homesteading/> [[Murray Rothbard]] criticized this doctrine as incompatible with his own homestead principle as a literal application prevent aircraft from traveling over someone's land,{{efn|name=hight-limits-note}} further arguing:
:But is the practical problem of aviation the only thing wrong with the ad coelum rule? Using the homesteading principle, the ad coelum rule never made any sense, and is therefore overdue in the dustbin of legal history. If one homesteads and uses the soil, in what sense is he also using all the sky above him up into heaven? Clearly, he isn't.<ref name=Rothbard-1982/>

So long as the aircraft did not damage or disturb the land, the owner would not have a claim.{{efn|name=hight-limits-note}} By the same principle, ownership of mineral and water resources on or under the land would also require homesteading, otherwise being left unowned.

=== Statutory law ===
In the 19th century, a number of [[government]]s formalized the homestead principle by passing laws that would grant property of land plots of certain standardized size to people who would settle on it and "improve" it in certain ways (typically, built their residence and started to farm at least a certain fraction of the land). Typically, such laws would apply to territories recently taken from their [[indigenous inhabitants]], and which the state would want to have populated by farmers. Examples include:
* [[New South Wales]]: [[Robertson Land Acts|Crown Lands Acts]] (1861)
* Canada: ''[[Dominion Lands Act]]'' (1872)
* United States: [[Armed Occupation Act|Florida Armed Occupation Act]] (1842), [[Homestead Act]] (1862)