As of early 2026, London Heathrow (LHR) remains the busiest airport in Europe by passenger volume, but it is not the busiest in the world. Globally, Heathrow typically ranks around the 4th or 5th spot. The undisputed title of the world's busiest airport still belongs to Hartsfield-Jackson Atlanta International Airport (ATL) in the United States, which handles over 100 million passengers annually due to its status as a massive domestic and international hub. Heathrow's position as the European leader is currently under intense pressure from Istanbul Airport (IST), which has newer infrastructure and more room for expansion; many aviation analysts predict Istanbul may actually overtake Heathrow for the #1 European spot by the end of 2026. Other global giants that consistently outrank Heathrow include Dubai International (DXB), which leads in international-only passenger traffic, and Tokyo Haneda (HND). While Heathrow is the "King of the North Atlantic" routes, its two-runway constraint limits its ability to regain the global top spot it held decades ago.