I will qualify what I am about to write by saying that I am not a lawyer. However, I am a patent attorney specialising in intellectual property (a form of intangible property, as opposed to real property). If the term "property" as used above were to encompass a right to operate an aircraft in a particular manner, then this "property" would presumably have to be some form of intangible right. However, when we consider whether something intangible is a form of property, we usually look to see if ownership of the property is something that can be transferred by way of assignment, agreement or by virtue of a particular law (e.g., employer ownership of inventions). At first glance, I can't see that the right to operate an aircraft in a particular manner per se could be transferred to another person. Although, when you purchase an aircraft, perhaps you are also taking ownership of that right. And, if you cannot then sell that right with the aircraft...
You are right Kaz, interesting to think about.