Do you mean specifically Russia? If so, the Russians were able to pull their troops back a lot more efficiently than the French. Since Russia has such a huge land area, Germany would have effectively had to create a line of aircraft that could bomb a huge expanse of space. The story of the Battle of Stalingrad is an example of how the Russians would also dig into the destroyed buildings and actually use them to their benefit as well. So the military mentality was also different.