The fine people at Popular Mechanics recently published a book that deserves a prominent place on every retrofuturist's bookshelf. The Wonderful Future That Never Was by Gregory Benford looks at technological predictions that appeared in the pages of Popular Mechanics from 1903 until 1969. The prediction below was an attempt to address what was seen as an inevitable problem; how to land personal aircraft in busy cities. The solution here was to erect a gigantic landing port supported atop four skyscrapers.
I have not read the book yet, but it looks great.