T4 is the largest terminal at New York's John F. Kennedy International Airport and the only privately operated terminal in the United States. Covering nearly two million square feet, T4 is home to 34 airlines, has over 12,000 employees, and serves more than 21 million passengers each year.

As of early 2026, the title of the biggest terminal at John F. Kennedy International Airport belongs to the New Terminal One (NTO), which began opening its initial phase of gates this year. This massive $9.5 billion project spans approximately 2.6 million square feet and is built on the footprint of the former Terminals 1, 2, and the site of the old Terminal 3. It eclipsed Terminal 4, which previously held the record at roughly 1.5 million square feet. The NTO is designed to eventually host 23 international-sized gates and features expansive, naturally lit public spaces, high-end retail "boulevards," and state-of-the-art security systems. It serves as a global gateway for major international carriers like Air France, Etihad, and Lufthansa. Even during its phased rollout, its sheer footprint and volume of passenger capacity make it the architectural and functional titan of the airport's multi-year redevelopment.