Leffers was assigned to a field telegraph battalion but, with his engineering background, was then reassigned to the
Fliegertruppen. After pilot training, he was posted to
FFA 32 in February 1915, flying over the northern part of the 2.
Armee sector. Starting as a
Gefreiter, Leffers rose rapidly through the ranks to become a
leutnant der reserve on the basis of his excellent performance in
reconnaissance roles flying
LVG B type aircraft. FFA 32's fighter element eventually became Jasta 1, and Leffers scored another 4 times with the Jasta. He received the Royal House Order of Hohenzollern after his sixth victory on 31 August 1916, and the
Pour le Merite in November 1916 after his eighth win. Leffers' seventh victim insists he was shot down by a
Nieuport; it seems Leffers used his captured French plane for this victory. On 27 December Lt. Leffers was shot down and killed in combat with FE-2b's of
No 11 Squadron RFC, the most likely victors being the crew of Capt.
John Quested and Lt. H. J. H. Dicksee. He was flying the captured Nieuport when he was killed. ==Awards and decorations==