[DoubleC]

I think 20000 a year is the magic number (maybe 25000).

Just like BA makes it one stop from here to anywhere, I'm sure a Seoul route could give Austin a gateway to the rest of Asia. Adding up the number of travelers of the other most traveled Asian cities:

Seoul: 22000
Taipei: 9108
Tokyo: 8797
Shanghai: 8594 (154.3% increase since 2003)

That's roughly 40000 to Asia. Assuming Korean Air serves those routes (or codeshares with other airlines), that's the number you're looking at if you consider travelers connecting at Seoul to their final destination. Though not everybody is always going to fly direct to Seoul, however. They might still connect elsewhere if it is cheaper or convenient.

Similarly with BA, you're going to see more than 36000 flying Austin-London because London might just be a connecting airport.