Spitfire F.MkXIVc
This is the premier British air-to-air fighter of WWII. It is my prefered mount and has been for years. This would be a perk.
A7M2 Reppu "Sam"
Designed by famed aircraft engineer Jiro Horikoshi as the successor to his A6M Zero-Sen, there were only 1-7 production Reppu airframes produced. It seems to have been the best performing Japanese fighter of the war and greatly impressed its Japanese and American test pilots. This would be a perk.
Ki61 IIb Hien "Tony"
A good mid-war IJA fighter. This would not be a perk.
H8K2 "Emily"
This would give the IJA, Japanese and Axis a decent 4 engined bomber. It was defended by 5 20mm cannon as well as a smattering of smaller weapons. It also had self-sealing fuel tanks and armor for the entire crew. Unfortunately, it only carried 4,000lbs of bombs or depth charges. It could also carry two torpedoes,and not those wimpy US or European torps, but the nasty Japanese ones. This would not be a perk.
P1Y1 Ginga "Frances"
This would give a survivable bomber to the IJA. This would not be a perk.
Ki84 "Frank"
This was the best Japanese fighter to see action in WWII. It would give the IJA a competitive fighter. This would not be a perk.
B7A2 Ryusei "Grace"
This was the best torpedo bomber of the war. It also had dive bombing capabilities and could be used from carriers. This would not be a perk.
S.M.79 II
This is a decent multi-role medium bomber and pretty much the best bomber that the Italians had. This would not be a perk.
Il2-M3 Sturmovik
This is THE major ground attack aircraft of WWII. If its full list of ordanance options were included, this would make a huge contribution to each sides offensive capabilities. This would not be a perk.
Mosquito FB.MkVI
This is the most common version of one of the most versatile aircraft, if not THE most versatile aircraft, of WWII. This would not be a perk.
Comments are welcome, as are your lists.
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We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother
Sisu
-Karnak