The He 72 Kadett looks rather like the Fw 44 Stieglitz, but the main landing gear is very different and there is a strut supporting the tailskid. According to the German Wikipedia, He 72 production terminated in 1937 after 768 airframes, including 495 built by Fieseler. It also says that 629 Kadetts remained in Luftwaffe service in 1940, and 417 in January 1944. The Werknummer (c/n) on the tailfin looks like 426 in this and another photo but I'm not sure. It is certainly three-digit, which would indicate a Fieseler, not a Heinkel c/n. The badge belongs to Flugzeugführerschule A/B 24, which was based in Olomouc, Czechia for most of WWII.

The He 172 was nothing more than a He 72 trainer with some aerodynamic improvements, notably a NACA cowling. The performance gain was disappointing and only two prototypes were completed in late 1935. It also seems that the Fw 44 Stieglitz was better liked than the Kadett by this time. Photo assumed taken in the winter of 1935-36.

Most probably the start of the massive 1938 German Air Rally. A reported 390 aircraft took part. In the left row are Fw 44 aircraft including D-EOQA and D-EGDU, third, which registration is listed as a Bü 131. Rangsdorf, south of Berlin, was opened as a sport airfield for the 1936 Olympics. The Bücker plant was located here. Lufthansa moved its flights from Tempelhof to Rangsdorf during WWII.

The second aircraft WL-IBYY is a Gotha Go-145A. Photo taken by my great-grandfather Willy Mägdefrau.