Well, in Porco Rosso, they did have Fio. At least, I count her as a strong girl: She's outspoken, charming, has her own mind, and goes along with her gut instinct no matter how much Porco tells her "no". Given how old-fashion he also is (and given the time period at the time), the fact that he character developed from her (and managed to respect her for both her skills and personality) is a major boost on why I love the character (and the movie in general).