In case you’re wondering how that 2 flight-a-day airport in the middle of Kansas supports international flights, to call themselves an “international” airport, they don’t have to.
Airports in the United States (and some abroad) are designated as an “international” airport if they have a customs service.
These customs services often are closed or on standby if there are no international flights. They remain there so an airport can be ready to handle a flight from another country. The designation is a small prestige boost and likely small tax burden. If anyone know more about this, tell us in the comments!