San Diego is one of the largest metropolitan areas in the US with about 3 million people living in the vicinity. However, the city lacks a large airport and the present airport is a small stretch of dangerous runway which handles too many flights than it can handle.
There is also no space for the city to have a second airport. Thus, the nearby Pacific Ocean expanse is the only area where an airport could be built, like they did in Hong Kong. However, the Pacific is too deep for rocks and boulders to be sunk and an airport built over it.
Thus Adam Englund, a local lawyer and visionary ahs come up with the idea of a floating airport or rather, a floating city. The structure would float on the surface of the ocean about 10 miles away from San Diego shore, and it would also come with a free space of 200 million square feet which is enough to have a city in itself.
Thus, it would open up to possibilities of large residential areas, offices, complexes and other business apart from the airport which would sit on the top of the floating structure.
Unfortunately, the guy has not got the permission from regulatory bodies. We shall have to wait and watch if this plan ever takes off. Oh yes, it is also environmentally friendly.