As a kite! In May 1940 the German army faced a superior Anglo-French force. The Latter was better trained, better equipped, and by far a larger force.
But Hitler had an ace up his sleeves – better generals. Generals that understood all too well that the key to success was to flank the allied forces with speed. So speed they got or rather took, and in numbers, big numbers!
German high command decided to “feed” its storming troops with Pervitin – a drug now known as crystal meth – with a touch of cocaine.
The German forces that previously suffered from low morale, suddenly exhibited self-confidence, concentration, and willingness to take risks. They hardly felt pain, hunger, and had little to no need for sleep.
They reached the strategically located town of Sedan within just 3 days and nights, in what was estimated by allied forces would be two weeks’ campaign.
Bonus fact: an additional critical flaw that brought the downfall of the French army, was its commander failure to understand the importance of communications.
While the German army enjoyed real-time radio communication, the French General, Maurice Gustave Gamelin, refused even to install a phone in his Paris headquarters in fear of security risk. Thus, his forces had relied on field telephone lines that were frequently cut off by German bombardments and on dispatch-riders that were stuck in roads clogged with refugees. Namely, even if Gamelin had something smart to say about the situation, it was irrelevant by the time he received the message, not to mention by the time it got back to the French front line.