[Gazz6666]

To be honest, if you wanted a definitive list of aircraft that *could* be included in IL-2 using the *current campaigns*, here's an list for you

Russia (Not so good with Russian aircraft, but I know some American aircraft were sent to/bought by Russia)
- B-25 Mitchell
- P-63 Kingcobra
- MiG-1 + 3
- Petalyakov Pe-2 + Pe-3
- Petalyakov Pe-8

RN
- Fairey Firefly
- Fairey Battle
- Fairey Fulmar
- Fairey Swordfish
- Blackburn Skua/Roc
- Martlet IV (Wildcat)
- Grumman Hellcat
- Grumman Avenger
- Chance-Vought Corsair

RAF
- Spitfire Variants
- Hurricane Variants
- DeHavilland Mosquito
- Boulton Paul Defiant
- Bristol Beaufighter
- Gloster Gladiator
- Hawker Tempest
- Hawker Typhoon
- Westland Whirlwind
- Avro Lancaster
- Avro Manchester
- Handley-Page Hampden
- Handley-Page Halifax
- Vickers Wellesley
- Vickers Wellington
- PBY Catalina
- Short Sunderland

USAAF
- Curtiss P-40 Kittyhawk
- Lockheed P-38 Lightning
- Northrop P-61 Black Widow
- B-24 Liberator
- And for christ's sake, a P-47 for everyone!

I might list some German and Italian aircraft later, it took a while to look those up and where they served.