Naming major city ISP POPs by IATA airport codes is a practice that goes back to uunet/AS701 in about 1995, maybe a bit earlier, when talking about reverse DNS for public IP space. It actually predates the existence of ARIN, even.

then appending a number, so your first POP/core site in the DFW area might be DFW01, then DFW02, DFW03, and so on.

On an international scale another non-airport or IATA related method is to group by ISO standard two or three country codes and then state/province/regional internal subdivision two letter abbreviations, so something in the bay area of california might have the last part of its DNS name as sfo01.ca.us.as12345.net

I prefer using the [United Nations Code for Trade and Transport Locations](http://www.unece.org/cefact/locode/service/location.html) (UN/LOCODE) value based on the address of the host's data center. It covers more specific locations than something like the IATA airport codes, and is still a well defined standard.

FWIW this is a very wide practice in the industry.

From my understanding it's more of a "what's the most well known airport". Google LA is in Venice, so it's closest airport should be SMO, it's still referred to in corp speak and machine naming as LAX.