JF Ptak Science Books LLC  Post 950 

Norman Bel Geddes (1893-1958) made fast, bulbously sleek and varyingly aerodynamic objects and ideas, and was a  vastly successful designer of things ranging from sets for the NY Metropolitan Opera House to telephones to cars to locomotives to the housing for the Mark I computer.  Ideas were his metier, and there seemed no lack of them–good, mostly; bad, sometimes. 

Bud bad ideas can be beautiful, and elegant, if only for a very short period of time in which they might have actually functioned for the good.  One of these blisterers was his floating airport for the NYC harbor.  Passengers would access the airport via a 800-foot automatic walkway tunnel, and then up to various shuttles and such on the levels below the flight deck. This beast floated on columns floating on mobile caissons just above the harbor bottom, enabling the whole to be turned into or away from the wind, making for easy approaches and departures for the planes. But it is the pilot of the airport that seems most interesting to me, steering the giant propellers that lay under the corners of the structure, pushing the airport into/away from the wind. 

This may well be the largest mobile steerable structure moving along the shortest courseway conceived as a possibly-buildable project of the twentieth century. 

Associated posts on great and unbuildable architecture:

Gigantic
and Unbuildable Buildings: Leroy Buffington, 1889

Fantastic
and Unbuildable Architecture #6: the Pyramids of Gizeh in Detroit
(Michigan),
1908

Gigantic
and Unbuildable Architecture: Bucky Fuller’s Midtown Manhattan Dome, 1968