purchased a minor ic, as japan,in alaska, on last turn. want to build an air base next turn. not sure if the base counts as one of the three units as per the limit. I would think not since you can place a base anywhere, even without an ic.
I feel a MAJOR IC in Norway is a still better idea.
I tend to build one in Poland as well: churn out infantry and artillery on turn 3, mech and tanks on turn 4 and so on. From Poland they can go either North or South, from Romania only North…
There was an area called the Black Zone where land based planes could not patrol due to range, however when they developed longer ranged aircraft the German subs had nowhere to hide.