Passengers check in, clear security, wait, and board aircraft from a dedicated building at the airport. That building is a terminal. It organizes the flow of people and bags between ground transport and aircraft.

Terminals contain check-in halls, security checkpoints, departure lounges, gates, baggage claim, and arrival corridors. Retail and dining occupy the commercial spaces between. Signage, wayfinding, and walking distances strongly affect passenger stress. Large airports operate multiple terminals connected by transit systems.

Design must balance capacity, security, commercial revenue, and passenger experience. Crowding at peak times tests even well-planned buildings. For most travelers the terminal is the defining physical environment of air travel.

A calm, clear terminal makes the complexity of aviation feel manageable.