If it works in Quito:
[Mariscal Sucre International Airport in Quito, Ecuador | image source]
Then why not in Manhattan?:
[Proposed Manhattan Airport by The Manhattan Airport Foundation | image source]
Oh wait, Mariscal doesn't work, which is why a new airport is being built 20km (12.4 miles) east of its current location, set to open in 2010. Nevertheless The Manhattan Airport Foundation is proposing the transformation of Central Park into an airport, a "viable and centrally-located international air transportation hub in New York City for the benefit of all New Yorkers."
Obviously this isn't a serious proposal, but the web page is presented in such a way -- particularly its assured and persuasive language -- that the project seems to mock proposals of this type, large (infrastructure) projects that purport to help people but have detrimental effects that offset the apparent benefits. Here the downsides are particularly obvious, with noise, fumes, heat, aircraft clearances, and the appearance of an airport in the middle of Manhattan being at the top of the list.
The answer to the FAQ, "I own an apartment alongside Central Park. What will Manhattan Airport do to my property value?" reveals the dry satire in the proposal, many notches down from The Onion. Statements that "these types of transformative public works projects have created an influx of interest and new investment in the neighborhoods in which they have been built" and that the area would "experience the economic 'trickle-down' effect these types of large scale redevelopment projects have precipitated time and time again" are clearly false, though they sound awfully persuasive here.
I'm not sure who's behind this fake proposal, or if it's worth the time and effort in creating the text and images, but I'm almost certain the combination of skilled writing, crude 3d images and professional-looking web page will fool many people in thinking the proposal is genuine.