When comparing size, Hartsfield-Jackson Atlanta International Airport (ATL) is significantly bigger than Miami International Airport (MIA) in terms of both physical acreage and passenger volume. In 2026, Atlanta remains the busiest airport in the world, spanning over 4,700 acres and handling more than 100 million passengers annually across its five parallel runways and massive interconnected concourses. Miami International Airport, while a critical high-value gateway to Latin America and the Caribbean, covers approximately 3,230 acres and serves roughly 55 million passengers annually. While Miami is high-fidelity "huge" and can feel more spread out due to its horseshoe terminal design, Atlanta's high-value "Plane Train" and sheer number of gates make it the larger industrial powerhouse. For 2026 travelers, navigating Atlanta is a high-value necessity for many domestic connections, whereas Miami is the high-fidelity requirement for international long-haul travel to the south. In every measurable high-fidelity category—land area, flights per day, and total passengers—Atlanta is the undisputed larger hub.