With the meter stuck on a pole at the parking space, if I pay for an hour but leave after 20 minutes, the meter still shows time. Somebody else can come and park there for 40 minutes, free.
But if I buy a paper receipt and stick on my dashboard, and leave after 20 minutes, the next person still has to rent the same 40 minutes of time.
Nobody I mention this to is upset about it (neither am I, at heart, though I do notice it). That suggests to me that conflicts over tray space on airplanes is driven more by a sense of claustrophobia and powerlessness, than by any particular notion of fairness or ownership.