Armored Combat
Back in mid world war one, without armor and air capable of ground support it looked like this
offensives might lead to breakthroughs, but reinforcements always sealed it off before the advance caused trouble. Attacking infantry just couldn't outpace railway borne infantry and guns.
Between the wars the german general staff decided that concentrated air providing ground support and massed armour columns could change that. Air would paralyze movement of reinforcements while massed armour had the pace to wreak sever damage and isolate large sections of the frontline. Here behind the front line the air forces and armored columns are massed ready for action
Now the massed air and one armor unit crush the French forces at Sedan, creating a breakthrough
then the massed armored columns pour through in the exploitation phase to isolate the front line and capture key targets
all the French forces are isolated since supply cannot be traced to them. Even those in the South, since armour units exert a Zone of Control (zoc) in each hex around them. Supply lines cannot be traced through an enemy zoc.