Bushrod, thanks for your insite. Since the folks on "Aerodrome" do know a lot about WW I aviation, I would think that MvR did have a Luger on his person for what ever reason. Perhaps it was to be for "signaling" among other things. Some of our WW II fliers carried a handgun for this purpose, attracting the attention of rescuers.
I don't know if German Officers purchased their own handguns or not. I know that English Officers did at some times.
BTW, my Luger is a DWM made in 1910. The first year of date stamps according to folks in this forum.
Lock and Load!