I personally find little value in that thesis, which has been lately paddled by Norman Ohler in his book on drugs and the Nazis. I have written before about this here, here, and here and I stand by my assessment:

But Ohler, in a fashion charateristic for bad or shoddy scholarship then goes on and attributes the success of the Blitzkrieg campaigns in Poland and France to Pervitin. His argument is simple: If Wehrmacht soldiers hadn't had Pervitin, they wouldn't have been able to drive a tank or fly a plane in a manner that is required for a Blitzkrieg campaign. And while there might be some truth to that statement, it also makes the problem of monocausal explanations pretty obvious:

In a modern military campaign, it doesn't matter if you can drive a tank or fly a plane for a very long time, if you have no gasoline and ammunition. Or if you don't have a clear plan on where to drive and fly. The success of modern military campaigns hinges on more factors than soldiers' stamina. To explain such a complicated historical phenomenon, it simply isn't enough to chalk it up to one particular factor only. The German victories over France and Poland were the result of planning, logistics, good tactics, and in the French case, a demoralized enemy. It can be asserted that in a limited way, the success of some campaigns relied on the use of Pervitin in its assumptions but to claim them to be the sole factor for victory is overstates, monocausal, and, simply put, historically inaccurate.

In short, while drugs might have been a minor aspect in the success of Blitzkrieg campaigns, the real reason they succeeded was down to logistics and planning, not to drug use.