Great quote on the loss of Norway:
“The gain to Germany was immense. In the course of a few weeks the entire Allied maritime situation in northern waters had been transformed. For Britain, instead of a friendly neutral across the North Sea limiting the area of naval patrol, there was now a hostile coastline dominated by the long-range bombers of the Luftwaffe; the tenuous patrol-line had been thrown back to the island chain = Orkneys, Shetlands, Faroes, Iceland – leading to the Denmark Strait and the icebound Greenland shore. At one stroke Germany had secured the vital iron ore route, had all but broken the stranglehold of naval blockade, and had gained for her armed forces what Hitler called ‘a wider start-line against Britain.’ Well might Raeder find satisfaction at the result of his nefarious plotting.”
From p. 41 of “Silent Victory” by Duncan Grinnell-Milne (this is a wonderful little 1958 paperback, which tells the story of Raeder’s doomed effort to come up with a way to invade Britain in the face of British sea power and with only grudging support from the Luftwaffe).