Kozhevnikov - is pleased widespread surname, and I have found some pilots with such surname (one even the general), but all of them flied in WW2 or later. I shall look else. It became interesting to me too. Surnames Kozhevnikov and Sapozhnikov are similar on ethymology, and Sapozhnikov - well known pilot of Civil War in Russia. But, as far as I know, he did not fly on the German airplanes. For this reason I have asked his surname.