Oh well, it was sort of interesting and I am somewhat suprised to hear that there are apparently no underground terminal buildings.
I thought though that in one of my several experiences in the ranks of SLF I transitted between two gates at an airport in Washington where we walked underground, but the details are rather hazy which is hardly suprising as I would have been about 20 hours into my trip by then.
Meanwhile, I will go on dreaming of my airport design, parallel runways with a row of 'angle parked' airliners between the runways.