It was 1919. The aeronautical technologies developed in war would be put to peaceful use in commercial aviation. London needed a proper airport as a central hub for air traffic. The October 18 issue of the Illustrated London News suggested this wacky design: a curved ring resting on top of the skyscrapers of the city.
What could possibly go wrong?
In this case: nothing, because it was never built. This ring was one of many early design concepts for airports. You can see more eccentric designs at Ptak Science Books.