I suggest "Flames in the Sky" by Pierre Clostermann, as it has about 8 chapters, each on a different flyer and nation in the war.
(You can't go wrong with "Samurai" either, or "Wing Leader" the autobiography of Johnny Johnson,
or "The First and the Last" by Adolph Galland, either)
To save a bit of money, I suggest you check out the WW2 and Aviation sections at your local used book store.
Kopfdorfer