Naples International Airport is located 6 kilometres from the regional capital of Campania.
The airport consists of two terminals, Terminal 1 and Terminal 2, the latter being situated at a decent distance from the main building.
The official website of the airport is https://www.aeroportodinapoli.it.
From the airport to Naples
In addition to taxis, you can also get to the city by bus.
You can take the 3S Line public buses to Piazza Garibaldi in the Old Town.
This is also where the metro station is located.
That bus leaves every 30 minutes.
The airport also has an Alibus bus service that will take you to Piazza Municipio, one of Naples’ main squares.
Nearby is the train station.
The Alibus buses leave every 20 minutes.
Tickets cost 3€. You can buy directly from the driver.
The airport is not far from the city, so the journey time will not take more than 10 minutes.
As for taxis, a comfortable ride will cost €20.
From Naples to the airport
Given that the only public transport (apart from taxis) linking Naples with the airport is by bus, the choice comes down to the two previously mentioned bus routes.