If you only have hand luggage and your boarding pass, do use Terminal C for going through security. Any flight or airline, super quick, took me less than 10 minutes ????
There train ticket machine outside the airport only takes coins and always has a queue. Instead buy your ticket to town at the tourist info. It's usually quiet.
Some better airporty deals: cheapest water o.5l carat for 1 EUR at Heinemann, most tasty cheap snack is the Minierollbrot from Marche for 4.5 EUR, cheapest coffee from Quickers for 2.5 EUR
It’s not a great airport to be honest. But the story around it is unique and keeps the whole city - if not the whole country - talking. Such untypical efficiency is unheard of!! ????
Pretend you don't know how much the local bus fare is (ask in english), and enjoy the evil eyes on the deliberately surprised faces of the bus drivers.