Imperial German Aviation Troop Field Aviation Department 41 Sleeve Badge

Imperial German officers who had been transferred from other military branches 
to the air force often continued to wear their old uniform,
only with new shoulder boards. For these officers, it was stipulated in a 
decree of July 26, 1915 
that they would have the propeller on their shoulder boards and the number of the 
flying department on their left upper sleeve. 
The Field Aviation Department 41 was formed on September 13, 1914 from the 
Aviation Battalion No. 1 and was deployed on the Western Front. 
Measures 4-1/2 X 1-3/4 inches.