Ok
I like the aircraft designer, but I wish air combat was made more visual or interactive. Similar to naval combat, I find myself not really paying all that much attention to what exactly my planes are doing. It takes away from the enjoyment of designing because it feels like I'm not really making an impact with my planes regardless of their design. The Italian focus tree is pretty fun, and the Ethiopian and Swiss trees look alright too. But other than that, it doesn't really add that much, especially for 20€.