Thank you very much, Kjetil, that's a wonderfully comprehensive answer and, I might add, an answer I was not expecting! I never would have thought of wood planking on top of concrete in a thousand years. It still does not make a lot of sense to me and I am not aware of Luftwaffe airfields being constructed with a wood cover over concrete elsewhere outside of Norway and probably Finland. There must have been some danger of blown tires from large, sharp wood splinters puncturing them during landing, I would think. I cannot help but suspect that there must have been some other reasoning involved besides rain drainage and protection for the concrete in case of air attack. If not, then it is strange that the Luftwaffe would not have used this method for other airfields in Europe where heavy rain and air attacks were a problem. There certainly was no shortage of wood and sawmills in the rest of Europe at that time so the raw materials (trees) and the means of production were available. This all comes as a strange surprise. I am enlightened yet still puzzled!
Larry
P.S. I am quite sure your book idea would be welcomed by many!