This paper has tried to analyze the impacts of Haneda Airport`s expansion on Japanese major competitive airports such as Narita and Kansai as well as Incheon Airport which is directly competing these airports in terms of hubbing. The analysis shows that Haneda Airport has increased departing passenger numbers while it decreased transfer passenger numbers although its expansion of traffic. And the other japanese airports showed huge decrease of departing passengers as well as transfer passengers after Hadena`s expansion while Incheon Airport has showed huge increased departing passenger numbers and comparatively minor decrese in transfer passenger numbers compared to all japanese airports. It is found out that Korea should learn from the japanese case and try not to follow same mistakes. Roles and responsibilites of two port system in Korea has to be made in proper manner and Incheon Airport should be consistently considered to be developed as a hub of the region in order to have its competitiveness.