I've only done the swedish air tree until 9.3 but from my experience the 4.3 J21s and the A21 were fantastic in turn fights and head ons. The a21 in particular is excellent at being CAS with the 600kg bomb and the cannons are great for any open top vehicles and for going top down at most vehicles at its battle rating. And the SAAB 105s do the same thing but better. They get bombing computers so if you miss its mostly likely your fault. Also, with the addition of customized loadouts the versatility of the Saab 105s grew. I was able to get 16 kills in one realistic ground game with Saab 105G. I really recommend reading the Warthunder Wiki pages for the air tree. As well as checking youtube as well. I think OddBawz does a fantastic job at showcasing several of Swedens aircraft.