There are many gaps to fill, and the most effective solution for HTC is to start with main arena survivable planes. This will change with AH II entering.
There are not many early war planes left that would survive well in the MA. Hmm. Beaufighter, D520, P36, Oscar, Rata, P39 and that's about what I can remember.
There are a couple of late war monsters left....Notably Frank, then P63, A26, P61, etc...
Eventually, HTC will run out of planes...
