You can BUY the 24 drogues, if you've got the cash to spend. But when you try to launch them they will simply vanish. (along with your PP.) Bascially, don't try it.
Basically, ships that use the PF engine can only buy a single drogue and this works fine. Carrier ships use the fighter engine, and they don't like trying to launch PF's. It's a rule that takes care of itself.
But, just in case someone has found a hole in the game logic, I'll restate here: No more than one drogue per ship. Ever.
-Herr Burt