I wouldn’t be so quick to call the landing strip idea an UL. The Interstate Highway system was definitely built with a military application in mind. The following comes from a recent on-line article called 40 Years of the US Interstate Highway System.
“One of the principal reasons for building the interstate highway system was to support national defense. When the system was approved — during one of the most instable periods of the Cold War, national security dictated development of an efficient national highway system that could move large numbers of military personnel and huge quantities of military equipment and supplies.”
I’ve also been told (though I just did a search and couldn’t find a cite) that the Insterstate overpasses were designed in such a way that even if they were destroyed (bombed, sabotage, etc) military traffic could be routed around them. If you look at most of the overpasses built through the early eighties, this appears to be true. I think after a certain point, they relaxed some of the war footing regulations to take into account the realities of the new, tighter, American landscape.
Also, I know that if *I</> were building a national, intercontinental road system during a time of high international tensions, I would take the opportunity to make sure that parts of it cold be used as impromptu landing strips.
As I said, no cites, but makes sense to me.