WWII Belgium

1941 cover from L09859 Luftgaupostamt Brussel, black eagle cachet, FELDPOST cds, to Berlin

cover from Luftgaupostamt, Brussels, from Saar Theatre group, with violet "Feldpostnummer 00138" cachet and FELDPOST cds, also another similar cover from the same sender with a different (but indistinct) Feldpostnummer