I have amended the league rules, effective immediately, to be clear about fighters on allied carriers (rule 10).
Basically says you need to be declaring fighters on carriers when there are allies involved. Preferably in the “game notes” feature of Triple A.
If you don’t declare, they are assumed to be on their own power’s carriers if there is ambiguity.
Declaration every turn is not always necessary because a declaration from the previous turn and the course of events dictate that there is only one possibl combination, but it is good practice to declare after each turn, whenever it is not totally obvious.
Read the rule, too, see what you think.
This rule is way overdue, even though I haven’t had disputes about this ever come to my desk.