How many parking spaces fit in a standard airport stand? Lets assume its a wide body stand, so something like 65mx80m, fits something around 208 spaces (using standard UK space size of 2.5mx5m with a 6m road). Assuming that the airport averages £35 a week and fills 75% of those spaces the annual income PER STAND is somewhere in the region of £300,000. For five stands that would be approaching £1.5 million.
Given the substantial discounts operators get on published parking charges, rebates, etc I suspect passengers pay for parking their cars is much more profitable than airlines parking their aircraft!
I do have to wonder though. In years gone by (lets say 2007, the previous peak) where did people park? Did more people get a lift/taxi/public transport to the airport? Or maybe use 3rd party parking?