I found a pair like this very recently, they are in restauration process right now.
Mine are stamped with the “winged propeller” plus “1917”, plus “Döberitz”
The Germans not only used British flying kit (and even fug boots as we know) but copied it. German WWI flying kit isn't my thing put I'd wager your boots are German copies of the British version. The British versions have straps with buckles at the ankle, just below the knee and have an adjustable strap at the top which was supposed to attach to a button at the waist.
Thx, have not seen british ones yet.No they're not British Boots, Thigh Pilot, although you can clearly see the influence.
....locked up in museums and collectors homes...Ooh, suits you sir! The German pilot on the left looks like something out of a bad 50's sci-fi movie, quite scary!! Mind you in the days of open top cockpits you wouldn't care too much about what you look like I guess. Surprised some of this stuff is still around and not all locked up in museums.