Do a search for 'South Africa' - the cities it returns are all small cities which are just big enough to have airports. In the cases of places like new york, only the airport is returned.

I'm just guessing here, but possibly this is a database of geographical locations with a population figure attached. The author has probably swapped 'only show cities with greater than X population' with 'only show cities with less than X population'. Airports would have very low population, and that's why there are so many airports. It also doesn't handle non-ASCII characters.

It's a guess, anyway.