Bought these nice prints from a fellow in Lomma,
His parents who fled from Hamburg during the war had these on their living room wall when he grew up in Sweden.
I found some information on the calendar:
Luftwaffe Calendar. 52 Photos. One page per week 52 pages in total. Issued only to senior Luftwaffe Personnel. Photos show Bf 109 (Me109), Bf110, Ar196, He111, Ju88, Do17, Do217, Fw190 and Ju87 Stuka Aircraft in service up to the date of issue from Heinkel, Messerschmitt, Dornier, Junkers, Henschel and Arado. Method of printing was lithograhy using stochastic screens (random dots, no half tone) in order to apply process colors. Color printing at this time was an art that was very much in development and consequently some pictures have retained their photographic quality more than others. It is easy to pick the photos which were shot as "black and white" and colorized at the behest of the Luftwaffe and opposite to these, the ones which were shot in color from the very beginning.