stanbrown wrote:
While I'm at it--on a different point that has confused me since I was a kid: Superman's key to the Fortress of Solitude being disguised as an airplane direction marker. Are there or were there ever such things as airplane direction markers in the arctic?

OK--so I was wondering if there ever were such things as airplane direction markers.  Today I see this story.  Not in the Arctic, but the air mail route from New York to San Francisco dotted with concrete arrows that were painted bright yellow--put there in the 1920s, those pre-radar days.

Now I wonder if these concrete arrows figured in any pulp magazine stories? Would the Fortress of Solitude key be the only their pop-culture connection?