항공․철도 공급과 국내선 항공수요의 상호 인과관계 분석:계량경제와 머신러닝 방법론을 중심으로

This study explores the intricate causal relationship between domestic inland route demand and railroad supply, emphasizing the pivotal role of supply-side factors in socioeconomic development. The introduction of KTX has led to a sharp decline in domestic inland air travel demand, posing substantial challenges for regional airports. Consequently, understanding the causal interplay between railroads and inland route demand is essential for devising effective strategic responses. To address this issue, we employed a dual-method analytical framework: a Granger causality analysis incorporating supply and demand indicators for both airlines and railroads, complemented by a random forest analysis integrating key socioeconomic variables. Our findings reveal a profound interdependence between railroad supply indicators and domestic inland route demand in the post-KTX era, with both sectors exerting significant influence over each other. This strong correlation underscores the need for a meticulous evaluation of railroad supply dynamics as a potential lever for revitalizing domestic inland routes. Moreover, our analysis highlights that inland route demand is not only shaped by structural supply factors but is also highly responsive to policy interventions and regional sentiments, exhibiting a notable ten-year lag in aircraft flight frequency. These results suggest that while preventing a decline in supply is imperative, sustainable long-term demand recovery may be more effectively achieved through targeted demand-stimulation strategies. Even after accounting for exogenous influences, railroad supply variables emerge as key predictors of inland airline demand, underscoring their fundamental role in comprehensive forecasting models. This research seeks to provide rigorous academic insights that can inform practical policy measures aimed at revitalizing regional airports and restoring the vitality of domestic inland air travel.