Hokkaido International Airlines, commonly known as AIR DO, is a Japanese regional carrier based in Sapporo, Hokkaido. Founded in 1996, the airline was established to provide lower-cost air travel between Hokkaido and the Japanese mainland, breaking the dominance of larger legacy carriers on those routes. The airline operates scheduled passenger services primarily between New Chitose Airport in Sapporo and major Japanese cities including Tokyo (Haneda), as well as other domestic destinations. AIR DO has historically focused on offering competitive fares to residents of Hokkaido. Following financial difficulties in the early 2000s, AIR DO entered a code-share and operational partnership with ANA (All Nippon Airways), which became a significant stakeholder. The airline is a member of the Vanilla Air and subsequently aligned more closely with the ANA Group network, benefiting from shared resources while maintaining its own brand identity.