No, flights between the U.S. mainland and Hawaii are strictly domestic flights. Because Hawaii is the 50th state of the Union, you are traveling within the same country. This means that U.S. citizens and legal residents do not need a passport for these flights (though a government-issued photo ID like a driver's license is required for TSA). You will not go through Immigration or Customs upon arrival in Honolulu or Maui. However, Hawaii has unique agricultural regulations to protect its delicate ecosystem from invasive species. Before landing, you must fill out an Agricultural Declaration Form, and upon returning to the mainland, your checked luggage will be scanned by the USDA to ensure you aren't carrying restricted fruits, plants, or pests. While the long flight time (5 to 11 hours) and the tropical atmosphere may make it "feel" like an international journey, it remains a domestic trip with the same legal and boarding protocols as flying from New York to Chicago.