Whatever the maxim cuiusest solum may have signified to the common lawyer of earlier centuries, it has since become obvious that its legal meaning is now heavily qualified by the advent of more recent technologies. For instance, fee simple ownership cannot possibly confer on the modem landowner a limitless dominion over the vertical column of airspace grounded within the territorial boundaries of his or her realty. Nowadays it is generally agreed that for legal purposes a pragmatic distinction must be drawn between two different strata of the superjacent airspace, the "lower stratum" and the "upper stratum" respectively. It is further agreed that the maxim cuius est solum ... has no relevance at all to the higher of these strata. Ownership of airspace usque ad coelum-if indeed it was ever taken wholly seriously--has now been commuted to a recognition that the landowner's property rights over airspace are restricted to the "lower stratum".
The upper stratum, it is said, "belongs to the world". It is the property of no individual and the property of no state. American courts have often referred to the upper stratum as constituting "free territory ... a sort of no-man's land". It is certain beyond doubt that, with respect to the upper stratum, the landowner "has no greater rights in the air space than any other member of the public". This "no-man's land" status of the upper stratum is significant in many ways, and indeed carries one implication which is of compelling importance in the present context. Although property law is intrinsically concerned with the allocation of resources, not all resources are--to use an ugly but effective phrase--"propertised". Contrary to popular perception the vast majority of the world's human and economic resources still stand outside the threshold of property and therefore remain unregulated by any proprietary regime. Lawyers, whose primary concern so often appears to be the allocation of propertised resources, would do well to be just as keenly interested when a particular resource is not propertised.