I read the book after seeing the movie also and, as you said, there are some interesting plot variations.
My comments regarding flaws in the artwork:
No ammo chutes for the guns.
Is the aircraft an all metal monoplane? I don't see any evidence of an upper wing and the fuselage appears to have an aluminum skin.
The goggles look like WWII RAF issue.
What is he holding in his left hand? Is it the top of a very long control stick?
BTW, I also recently read a novel that was turned into a movie; 'The Hunters' by James Salter. It is a fictional account of USAF fighter pilots in the Korean War. The movie is typical 1950s Hollywood fare with some decent flying sequences (imagine: Rambo flying F-86s in the Korean War). The book is quality literature in my opinion, vastly superior to the movie, and among the best historical novels I have read.