One of my favourite books - The story is a modern fairy tale for those of us who like WWII era aircraft , that said this novel isn't aimed solely at war-bird enthusiasts - The main characters of the story are fleshed out , they are group of WW2 pilots from both sides of the European war reliving a significant time in their lives - there are a lot of insights into the characters thoughts and the author uses that to reflect on the characters perception of how the modern world has changed both physically and in the way values have altered in the intervening years.
One reviewer described the book in a quite a dismissive and shallow way describing part of the story as perverted which I am assuming is reference to the main female character having thoughts , feelings including lust and sexual frustration and a marriage in decline all of this intertwined within a unique situation involving wartime Luftwaffe experten (aces) in a more modern setting - this is not a weird sci-fi time travel book but a novel exploring our love for re-creating the past (battle re-enactments , flying shows and museums full of lovingly restored aircraft) and what happens when that is taken one step further.
The author has built a credible world and inhabited it with interesting and engaging characters and this is why I would recommend Gray Eagles.