LAS is literally next to the strip

Another way of looking at it, the median population center line of longitude falls not too far east of the IL-IN state line, making ORD slightly more favorable from that perspective if considering US domestic travel. Though STL is not substantially far off in that regard.

I couldn't easily find (and didn't spend much time looking for) a mean or median center of population for North America as a whole. I'd guess it would be somewhat south of the US population center anyway.

Interestingly, the geographic center of the North American continent is in North Dakota...there are some disagreements on the exact spot but it seems the most recent measurement places it, ironically, near a town called Center, ND! :D Which wouldn't be relevant for the thread subject, but I found it mildly amusing.

It went through St. Louis on its way to Kansas, eventually.

Singapore
 

I thought HNL was strategically situated when I moved there, but it's easier to get to Mars than to Europe. Plus every airline views it as a vacation market and, consequently, dispatches its oldest, rattiest aircraft on that route.
IMHO, SIN is the best situated airport. Not only is it spotless, delightful and serviced by some of the better airlines, but one can easily go almost anywhere in the developed world from there via nonstops to Europe and both the US east and west coasts.

HNL, sounds like it would be agreat location, and initially in the days when really long flights were not possible, it was. But, if you look at a globe (or something like Circle Mapper), you realize it is really no where near any trans-pac routes - they all go way up. Which brings me to Anchorage. Ironically, the airline that has the biggest presence there doesn't fly international.

HKG has some of the same advantages as SIN and isn't so far south, although my vague impression is that HKG suffers more from weather disruptions (typhoons).

DFW but I’m bias

I'll give a biased vote to my hometown. ORD is about a 45 train ride from downtown but compared to our large city competition (LGA, LAX) it's a dream to get to downtown. Also, as a local, the ability to get nearly anywhere I want in one flight is one of the best gifts a frequent traveler could ask for. Now about those pesky winter delays... ;-)

A big city which hasn't yet got an international hub airport?
One obvious contender would be Berlin. Great public transport and located in a major city in Western Europe.
But Lufthansa have gone for FRA and MUC as their international transfer hubs.
Of course, they would have to finish the Schoenefeld improvements first.

You would find this very interesting. It’s a chapter called “Airport Terminals” from The Geography of Transport Systems (copyright 2017? But has data from 2018 and 2019 as well).

https://transportgeography.org/?page_id=3717

Actually I was about to type Sfo :-)