Ulsan Airport — Ulsan, South Korea

Ulsan Airport, identified by the code USN, serves South Korea's major industrial city of Ulsan, a hub renowned for shipbuilding, automobile manufacturing, and petrochemical production on the country's southeastern coast. Despite Ulsan's economic significance, the airport itself is comparatively modest in scale, handling primarily domestic routes to Seoul's Gimpo Airport and Jeju Island rather than international traffic. USN caters heavily to business travelers connected to Hyundai's massive manufacturing operations and the broader industrial complex surrounding the city. The airport's single runway and compact terminal reflect its role as a regional connector rather than a major international gateway, though its proximity to South Korea's industrial heartland gives it outsized economic importance relative to its physical footprint.