There are different departments located at each airport to provide service for each aircraft like passenger terminals, cargo terminals, etc.…
Passenger Terminals
In modern airports, terminal passengers should be located in such way that it can provide more relaxed and simultaneously faster service for passengers. If a passenger terminal accommodates more aircraft at a certain given time, it can be more profitable for airports.
Normally passenger terminals are being located in a place that can accommodate more aircraft in higher areas around it to load and unload passengers.
Cargo Terminals & Warehouses
Each airport should have different cargo terminals for accepting Export Cargo, Custom inspection, loading into Unit Load Devises, keeping them ready to be loaded into aircraft, and also for unloading Import cargo, placing them for custom survey and delivering to customers.
These terminals should have different facilities for General Cargo, Dangerous Goods, Postal items, Valuable items, courier materials, Diplomatic mail bags, Perishables, Live Animals, etc.…
Other related departments
There are different areas needed at the airport like Engineering department, Unit Load Device warehouse, Ground handling equipment, dollies, drivers, fuel department, customs, fire extinguisher dept, security department, catering, Car Parking, Taxi stations, banks, exchange office, restaurant, Hotels, etc.…
Ground Time & Flight Delays
Each aircraft has limited time to perform disembarking of passengers, cleaning, refresh catering, fueling, unloading of baggage and cargo and then reload the aircraft with Traffic load to continue the flight to next destination. This time is called the Ground Time. Any delay in performing all this, in pre-defined time limit will cause delays in next coming flights and may have fines for the airlines, caused the delay.
Delay will also cause change in flight plan and route of the flight to destination and change other aircrafts routing.