Imagine a beautiful summer day. You are enjoying the sunshine in your garden when all of the sudden a drone flies over. Although you may have some pretty good reasons (hello, privacy) to be concerned, is the airspace above your house and garden actually part of your property? Does your property reach all the way up to heaven’s gates? In this article, we will explore how in the 20th century a long-lasting principle had to make way for aviation and how legal theories are tested once again due to the disruptive technology of drones.
Long before men could soar through the sky, the adagium “Cujus est solum, ejus est usque ad coelum et ad inferos” dominated both doctrine and jurisprudence. The literal translation reads that whoever owns the ground, owns it all the way from heaven to hell. With other words: your property reaches as far as heaven’s gates, creating an infinite column of your airspace above it. Contrary to what the name suggests, this maxim does not have its roots in Roman Law. Studies show that the maxim can be traced back to the 13th century glossator ACCURSIUS. Through the Code Napoleon, this legal notion of property found its way in the civil codes of different countries, including Belgium (article 552 BW), the Netherlands (article 5:20 BW) and Switzerland (section 667 ZGB). Whereas in common law, jurisprudence as early as 1586 and doctrine from mainly W. BLACKSTONE formed the notion in England and the United States.
When aviation took off, it soon became clear that this legal notion of property from heaven to hell could not survive. In the beginning of the 20th century commercial aviation made a definite end to the ad coelum principle, since the development of this sector was impossible when landowners could potentially sue airlines for trespassing.
The upper stratum of airspace was deemed to constitute a res omnium communis (of common heritage of mankind), which could be used by all and constitutes navigable airspace. This view was consequently codified in the Paris Convention of 1919, and later in article 1 of the well-known Chicago Convention, that introduced state sovereignty above the territory.
This does not imply that landowners have no claim whatsoever on the airspace above their property. In the U.S., the famous Causby case made this clear after a very low flying aircraft - below 365ft. – caused the untimely demise of Mr. Causby’s chickens. The Court stated that “the landowner owns at least as much space above the ground as he can occupy or use in connection with the land”. In common law this triggered the principle that the portion of airspace that the landowner can reasonably use for the enjoyment of his land, is his property. Belgian jurisprudence limited the vertical property boundary to the space that is required for a normal exercise of property rights. Which means to the extent that the owner has a legitimate interest, for instance when the use of airspace could damage the ground. Although in the Netherlands the property does not extend to the air, the landowner still had the power to control this area, which results in practically the same result as in Belgium.
The ambiguity however still remains, since the precise boundary of the higher and lower airspace was never fixed. To which exact altitude do your property rights reach? Jurisprudence over the last decades determined at which height airplanes could cross this landowner’s right. Generally speaking, the line is usually set around 200ft.
A new player, though, has entered the stage. The disruptive technology of drones has caused the legal notion of property to be challenged once again. In general, drones fly up to 150ft high, which means they are soaring through the very low airspace that traditionally belongs to landowners. Does this qualify as trespassing, or should the boundaries be redefined?
The vertical dimension of property is limited by the area in which the owner has a legitimate interest to fulfil the normal enjoyment of his property. The question we subsequently need to ask ourselves is: does a landowner have a legitimate interest to ban drones above his property? And I am not talking about pure privacy-related reasons, in this case the scope is solely the property-related claim. As mentioned above, when someone uses the airspace above your ground in such a manner that it could result in damage to the surface, a legitimate interest exists. You could argue, that a loss of control could result in a crash which could damage your house or garden. However, property is above all a dynamic concept, that evolves in line with new technologies. Property today, may not exist tomorrow. The vertical boundary has been lowered before due to aviation needs. The ratio regarding drones is similar. Drones constitute a new and promising technology. Commercial drone operations in which long distances will be covered at low altitudes for purposes such as parcel delivery only have a chance to flourish when companies do not face claims from property owners. Airspace is after all a res commune. To protect house or landowners, lawmakers could opt to impose a minimum altitude that applies when flying over private properties.
Considering the change that was made to vertical property boundaries regarding aviation in the 20th century. It is not farfetched to imagine that the integration of drones, will lower the boundary once again in the 21th century. Interests of landowners will need to be balanced with economic interests of commercial drone operators to find a new balance to reshape the limits of property boundaries.
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