what collar tab is it ?

Undated photo of a young Pvt. Mathias Zerwas - relative of wife's side. In the spring of 1945 he would die when his plane was shot down over Budapest, Hungary and is buried in a mass grave with approx. 6000 German soldiers at the outskirt of Budapest. 

Pvt. Mathias Zerwas

Undated photo, probably from the early 1940s - relatives on my wife's side... In Luftwaffe dress uniform (rank unknown) is Mathias Zerwas (the lady next to him is his sister). Toward the end of the war he was shot down with his plane over or around Budapest, Hungary and is buried there in a mass grave for nearly 6000 German soldiers.