Let's consider fighter aircraft to keep the furballers happy. Depends on what you call 'early war'. The Japanese started theirs in China in 1937 and the Ki-27 would make a nice ride, as would the Gladiator that the Kuomintang Government purchased from Blighty and which actually made its combat debut over China.
Next up, Germany invades Poland. Oooooh yes, now we've got the PZL P.11c and earlier versions scrapping with Bf109Es and 110Cs. Meanwhile the French are sitting behind the Maginot Line polishing their Morane-Saulnier 405s and frantically developing the Dewoitine D.520 and Bloch 150-series fighters. Alongside them on French airfields are Hurricanes Mk.I, mostly unarmoured and many of them still sporting the two-blade fixed-pitch Watts prop.
In May 1940, the Phony War goes hot, more Hurricanes have armour and three-blade two-speed props, the French fighters are supplemented by imported Curtiss Hawks and the odd Douglas A7, the German 109s and 110s have gained a little more armour and quite a bit more weight but otherwise the Battle for France and the Battle of Britain are fought with the same basic types both sides have been flying for the past year or so.
22nd June 1941 is a VERY bad day for the Soviets, who lose thousands of their Polikarpovs I-15, 152 and 16 under the cosh of the invading Luftwaffe, which is still using basically the same aircraft that it used to attack Poland.
7th December 1941 - and the USA finally enters the madhouse that is World War Two. Cool, Aces High can now begin to model 'early war' aircraft.