International flights are air travel routes that connect different countries. These flights typically require passengers to go through customs and immigration checks, as they cross national borders. Airlines operate these flights, offering various services and amenities to ensure a comfortable journey. Travelers on international flights must have valid travel documents, such as a passport and, in some cases, a visa. The duration of these flights can vary significantly, depending on the distance between the departure and arrival cities. Popular international flight destinations include New York, London, and Tokyo.