This is the best strategy for Ravenfield. Blitzkrieg was invented by the Nazis in WWII and in German it means ‘lightening war’. It is a legitimate and innovative strategy for warfare between industrial societies, not just a Nazi thing. Ravenfield currently is not properly balanced against this and if done properly it can be used to great effect.
The idea behind Blitzkrieg is that you attack your enemy from the beginning hard and fast. Concentrate your forces at a single point to break the line. Once you break through, leave absolutely no breathing room for your enemy. Continue to extend your forces rapidly into the enemy territory until you can feel your momentum waning, and then hold the line. If done properly, you can start the match with a huge territorial advantage, and if very successful, you can completely overwhelm your enemy and win the match before all their forces are used up naturally.
The theory behind Blitzkrieg is that because of the destructive power of modern weapons an attack which breaks the line at a single point requires the enemy to immediately respond, and they cannot begin to make a comeback until they respond. Thus, the enemy needs a bit of time to consolidate the new line and mount a counter attack. If you can mount a further attack before he can do this, you can break the new line and make further progress.
This process of continually pushing and never leaving room to recuperate works as long as your enemy cannot mount a resistance. The Nazis used this to conquer Western Europe and push the Soviets to Stalingrad. The eastern and western fronts of WWII provide examples of the drawbacks and dangers of Blitzkrieg.
The first issue comes from the western front. Once the invasion of Normandy occurred, the Germans were not properly equipped to defend the continent against such a scale of attack. When conducting Blitzkrieg, if at any time you decide to hold the line, make sure you hold it!
The second issue comes from the eastern front. Both fronts had a similar problem, but Stalingrad is more illustrative. In Stalingrad, Hitler became obsessed with capturing the city even though his army was overextended and lost momentum. The Germans poured endless resources into something too fortified. When conducting Blitzkrieg, know that if you lose momentum it is not wise to keep attacking for the hope to restart momentum! If you lose momentum, you will not get it back. the only thing to do is focus on maintaining your position. Be careful not to overextend yourself, if you are overextended and you lose momentum, you will be open for counterattack and risk losing all your progress as the enemy can now easily march back through the lands you captured.
I hope this explanation of Blitzkrieg warfare helps and you can see how to use it in Ravenfield. Some maps are easier than others to conduct this form of war. Citadel and Glacier are both good places to try this method. Archipelago is another feasible one.