Gray was the branch underlay for mechanized troops, so is correct for an aviator who was wearing the uniform of the flying troops, not simply seconded from another branch wearing his old uniform with the device on his boards. Pear shaped straps are for Uhlan everyday wear-- having metal ones for parade dress. The Police cord was common in a number of Weimar Republic era forces, ranks varying from one to another between Wachtmeister and Hauptwachmeister. M1915 Oberst is from Infantry Re