Stefan Jovanovich on the Maginot Line
The French built the Maginot line in order to free up their mobile forces and to give them a chance to fight on equal terms against the numerically superior Germans. That strategy worked. The problem was that they and the British both assumed that the Germans would attack only through Belgium. Guderian's success in breaching the Ardennes was a near-run thing. They met opposition from French tanks - which were better; and if the British had devoted a fraction of the effort to bombing the Germans supply lines that they did to dropping leaflets over Berlin, we would not be having this discussion.
Henry: If you can give me a model for the "long, thin artillery shell" I would appreciate it. The only one that I know of for the period of blitzkrieg is the 8.8-cm Flak41, and that had barely come into service in 1941.
I believe your reference to the paratroopers "landing" onto the fortifications refers to the assault on the Eben Emael fortress in Belgium, and that assault was carried about by glider, not parachute drop. The Belgians, unlike the French, did not have their fortresses interconnected or supported by infantry. They believed that the canals would be sufficient deterrent. (One of the Germans' relatively unappreciated skills was their ability to conduct rapid bridging operations Some people have even suggested that the ease with which they crossed the Meuse and other water obstacles led the Wehrmacht high command to plan the invasion of Britain as if the English Channel were just a wider river.)