Ginger:
Winged Victory heads the A-list, but try Derek Robinson's trilogy: "Goshawk Squadron," "War Story," and "Hornet's Sting." All 3 are excellent.
On the lighter side, Donald Jack's Bandy series is quite good (you'll find yourself laughing out loud).
Also - although more naval than aviation - John Biggins' Otto Prohaska trilogy +1 (what do call a series of 4, anyway) is top notch. One of the books, "A Two=Headed Eagle," concerns a stint in the Austro-Hungarian Air Corps.
You'll find any of the above most enjoyable.
VBR,
Ira