I had the most comfortable 8 hour layover ever there. Other than being a bit heavy on soldiers, it's fantastic.

If they are publicly funded projects, there may be requirements for art installations. Denver for example has a "1% for the arts" law, so 1% of a project budget must be used on art to litter around that project. Denver International Airport (with its billion pricetag) is therefore packed to the gills with sculptures and paintings and pinwheels in the tunnels.

My problem with this is, who decides what is "art"? Why does one piece get selected for the installation, and not another?

If these airport installations are publicly funded, then they should reflect the will of the public. So screw the pinwheels, I want a fifty foot tall statue of Michelangelo fighting Bebop.

Part of the reason is attracting airlines to use your airport as an international hub.

Changi, Kuala Lumpur, BKK, even Inchion, all can be used as stops for flights that then lead into Europe, Middle east, Australia, or deeper into Asia. The plane takes off Sydney, lands in Singapore for a re-fuel and to collect connecting passengers, then off to Bangalore.

It's big business, airports charge for gate fees, PAX in transit spend money in the shops, and if the layover is long enough, they'll step out of the airport and see the city. There are yearly awards for best airport in Asia.

Changi is still the best, free movie theatre, butterfly garden, Koi ponds, excellent bars, good restaurants, the lounges are good, you can even go for a swim. Kinetic Rain is in terminal 1, the old crusty terminal. T3 has a 3 story slide for kids and adults and a full sized supermarket. You could live in that airport.