Would be nice to separate craft by country too.
Say, add a row of buttons above the current "fighter" "bomber" "vehicles" buttons.
So you would have something like this:
(US Marking) (British marking) (German marking) (Japan marking) (Italian Marking)
Fighter Bomber Attack Vehicle Boat
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So when you click on the US marking button, and you have the fighter button pressed, the menu only shows US fighters. When you press the german marking and the bomber button it only shows german bombers on list.