What if the Altmark incident never occurred and neither combatant goes after Norway? Without the Norwegian Campaign how does WW2 turn out after that? Both Germany and Britain don't experience the losses that occurred in the that campaign, which were proportionally more severe for the Germans, both navally and aerially. That said, the continued neutrality of the Norwegians also means the British don't gain their massive merchant marine, which added rough 40% (IIRC) to the prewar British shipping.
Also without the need to invade Norway, Denmark isn't invaded, so Iceland and Greenland are not then controlled by the Allies.
What does this mean for the Battle of France?