You could start with
http://www.ww2.dk/lwoffz.html
Henry L. deZeng IV and Douglas G. Stankey have been collecting a lot of information about Luftwaffe officers:
LARDY, Walter.
07.09.42 Oblt., appt Staka 16./KG 6 (to no later than 01.11.42).
29.11.43 Oblt., 4./ZG 26.
16.11.44 Oblt., appt Staka 3./JG 103 (to 27.02.45).
Credited with one victory.
Good luck with your book