The involvement of the Luftwaffe , however , was not entirely restricted .
A commonly held viewpoint is that the involvement of the Luftwaffe in the Civil War constituted a proving ground for troops employed later during World War II .
The involvement of the Luftwaffe , however , was not entirely restricted and a commonly held viewpoint is that the involvement of the Luftwaffe in the Civil War constituted a proving ground for troops employed later during World War II .