The newest version is Birds of Steel 5 https://scratch.mit.edu/projects/197844703/ Instructions are in the game. Press the green flag twice. Information on... Bf-109K4: https://wiki.warthunder.com/index.php?title=Bf109K-4 P-51D: https://wiki.warthunder.com/index.php?title=P-51D-5_Mustang
This is Birds of Steel 3 but the other way around. Also, I can't be bothered finding a P-51 cockpit, so I simply deleted it. I don't care whether you favourite and star it or not.
