WW2 Germany Stamps

1rst pic:
It was issued on February 11, 1944, to celebrate the 25th anniversary of the German airmail.

2nd pic:
In 1942, the British made near-identical copies of the blue German field stamp (designed only for German soldiers to mail letters home via air) so that they could overburden German airmail as a sabotage attempt.

3rd pic:
The green one is a 1938 Nazi-Party stamp (NSDAP.) The red is a Zulassungmarke Feldpost (Fieldpost) stamp that was first issued for Wehrmacht soldiers about 1940. They got one per month for letters up to 250 grams, but in 1942 it was changed to two per month. The blue stamp is the oldest and is a mid-1930s Nazi Party Dienstmarke stamp that appears to have been canceled (stamped 1946) rather than have been used.

4th pic:
Post-marked for 1944. Occupied territory stamp, if I recall.