Capacity planning is the strategic process by which an airline determines how many seats to offer across its network to maximize profit while meeting passenger demand. It is a complex balancing act involving "Available Seat Miles" (ASMs). Airlines must decide which aircraft types to fly on specific routes based on fuel efficiency and passenger volume; for example, flying a Boeing 787 on a high-demand long-haul route versus an Airbus A220 on a short regional hop. It involves fleet planning (buying/leasing the right number of planes), crew scheduling (ensuring enough pilots and attendants are available), and network optimization (timing flights to allow for connections at hubs). If an airline overestimates demand, they fly "empty metal," losing money on fuel and labor. If they underestimate, they lose potential revenue to competitors. In 2026, this is largely driven by AI and Big Data, which analyze historical booking trends, holidays, and even local events to predict exactly how many seats should be available on any given day.