D-Day was a triumph of logistics and planning. Eisenhower, in overall charge, was a logistics guy, which was exactly what was needed. D-Day was just the beginning of the invasion. The purpose of D-Day was to establish beachheads through which larger armies could be landed and then supported. The support function was key. Without extensive logistic support, the heroics necessary to force a hostile landing were pointless. The Dieppe and Dunkirk failures had clearly established this. Eisenhower delayed D-Day until huge support resources had been built up.
There were Higgins boats, in both infantry and tank sizes. There were Dual Drive tanks, Sherman tanks which could float, sort of, for a short while. (Many didn't make it to the beach, but those that did meant the troops had armor on their side.) There were "Hobart's Funnies", tanks with strange attachments to flail their way through minefields and barbed wire. There were the Mulberry temporary ports, sections floated over and sunk to create jetties to which cargo ships could dock and unload. Fuel pipelines were unrolled across the English channel to carry fuel in bulk.
In the later stages of the invasion, more and more support resources were ferried over and deployed. This included multiple mobile Coca-Cola bottling plants and mobile bakeries.
Eisenhower wrote that the conquest of Europe pretty much followed his original plan. Probably the greatest triumph of the waterfall method, ever.