BY if you think AC is paid for leave, sick days, ground duties, etc, do you also think he's paid to sleep, eat meals, go sailing and have days off at home? In that case, it'd seem you're correct. A month's salary for a whole month of anything.
If that is the case, then why is he paid for "credit hours" which do not include those items? It's hard to see why you don't agree that after 15days leave being rostered for 65 credit hours (and possibly some non-credit duties also) in the remaining 16 days is effectively doing most of a month's work in only half a month. Maybe I've missed the point but I've never heard people defending the current system until now.
Many years ago we used to be awarded I think it was 2.5hrs credit for a Leave Day. That's not being "paid" for leave but it amounted to the same thing. TCK changed that.