The Avengers dazzled us with the airborne Helicarrier — but if some visionary designers had had their way, we could have had airplanes landing on structures high in the air. Airports raised above cities, airports floating on the water... the 20th century had many schemes, but no success. Check out some of the wildest concept art.

A Landing Deck in Midtown Manhattan, New York City, from LIFE Magazine, 1946

"It is an airport built 200 feet above street level right over 144 square blocks of Manhattan's crowded, valuable West Side from 24th to 71st Streets and from Ninth Avenue to the river. On the top 990-acre deck, which is 12,000 feet long by 3,600 feet wide and is roughly as big as Central Park, are three parallel runways to handle plane traffic. […] The man who dreamed it up is one of the most successful and hard-boiled real-estate men in New York City – William Zeckendorf, vice president of the big New York real-estate firm of Webb and Knapp. He estimates the cost of his transportation center at $3 billion, $500,000,000 for the land and $2,500,000,000 for construction and financing. This, he thinks, can be paid off by rental income within 55 years after the project is completed." – according to the article of LIFE Magazine, found on Ptak Science Books.

(via Ptak Science Books)

A Rooftop Circular Airport from Illustrated London News, 18 October 1919

(via Ptak Science Books)

The scale model of the Edward R. Armstrong-designed sea-drone concept from 1927

(via Mechanix Illustrated, December 1952 and Collective History)

A huge wheel resting on the roofs of many skyscrapers in New York City, designed by H. Alvater, 1929

(via Urban Nebula)

Floating Airport on the cover of Air Wonder Stories, July 1929 (artwork by the legendary Frank R. Paul)

(via Pulpmags)

Concept art of a landing platform over the old Penn Station in New York City, 1929

(via America By Air/Smithsonian National Air and Space Museum)

An airport above London, from Modern Mechanix, September 1931

[…] A proposed airport to be located in the heart of London. […] The entire structure being supported by the buildings over which it is erected, as illustrated.

(via Modern Mechanix)

Over the Seine in Paris, designed by M. Lurcat, from Science And Mechanics, June 1932

(via Modern Mechanix)

An airport above the Thames between the Lambeth Bridge and Westminster Bridge, from Popular Science Monthly, January 1934

(via Treehugger)

Uncle Sam Asked To Build Floating Ocean Airports, from Popular Science, February 1934

You can read the whole article here.

(via Popular Science/Google Books)

An Aerial Landing Field That Uses Solar Energy Only, from Modern Mechanix, October 1934

(via Modern Mechanix)

Roof-top airport turns with wind, from Popular Science, January 1937

Mounted on roofs of office buildings, rotary airports may solve the problem of creating adequate landing fields within the limits of large cities. [...] Erected on a steel-girder foundation, the long, overhanging runway resembles the deck of a large naval aircraft carrier. Machinery housed within the supporting structure would turn the rotary airport so that planes would always be able to take off or land into the prevailing wind.

(via Popular Science/Google Books)

Floating Ocean Airport Gets Power From Waves, from Popular Science, May 1937

A floating landing field for transoceanic planes, just designed by a French inventor, utilizes wave-operated outrigger floats to generate power for its lights and propelling machinery. Operating through a system of levers, the floats drive large air compressors. The air is then used to run a dynamo for electricity and to drive the propellers which will keep the marine airport stationary against the action of strong winds and currents.

(via Popular Science/Google Books)

Another concept of an airport that it could automatically swing into the wind, from Mechanics and Handicraft, October 1937

(via Modern Mechanix)

A giant circular aerodrome over the city, from Mechanix Illustrated, July 1938

(via Mechanix Illustrated)

Floating Sea-Drome by Frank Tinsley, published in Mechanix Illustrated, December 1952

(via Modern Mechanix)

The concept of London Britannia Airport (LBA) by Gensler, 2012

An airport in the Thames Estuary, instead of the aging Heathrow, without any serious environmental impact? Why not?

(via WebUrbanist)