Hi,
The answer to this question is quite long.
First of all, at 1:400 scale, the space available is approximately 800 meters x 250 meters, and you have to decide whether to build a replica of part of a real airport or a fictional one.
Then you have to decide which part of the airport to build, basically choosing between a section of the apron or taxiways with runways and holding points.
Then you have to decide whether you want to create an apron/tarmac using a printer or build a completely homemade airport. I specialize in handmade airports, and I have to say that with sufficient skills and experience, the results are truly excellent.
After many years and regarding the tarmac, the apron lines and marks, I've discovered that every country and every large airport holding company has its own characteristics: for example, English airports have truly complicated apron lines and markings, while Greek airports had the characteristic of having round or semicircular parking lines (then, with the advent of privatization and the arrival of Fraport Greece, they all became the same and essentially schematic).
I recommend using Google Maps to create an airport as faithful to the original as possible. Even Greek and Turkish airports are now visible from satellites (until a few years ago, they were obscured because they were considered military sites. In fact, Santorini, for example, is also a military base with shelters for F-16s).
Regarding terminal buildings, the Herpa ones are absolutely primitive.
My advice would be to build the terminals yourself using balsa wood or plywood, a suitable wood glue, and then some decals with windows and everything else.
For the control towers, Die Cast Model is producing beautiful towers in 1:400, 1:500, and 1:200 scale. In 1:400 scale, Berlin Tegel, Berlin Brandenburg, Frankfurt, Hamburg, Dusseldorf, Cologne-Bonn, Munich, Vienna, Zurich, and Paris CDG are available.
On ebay and, sometimes Amazon, you can find good occasion to buy the models you need for your airport; there are also some private manufacturers for Terminal buildings, but you need to adapt them to the space you have and to the airport you want to realize.
For example, if you want to realize a round terminal builng like some of French overseas territories airports, you have to buy herpa round terminal buildings or to create a terminal building by yourself.
I hope to be useful. If you want more infos about handmade airports using plywood panels i will asnwer.
Regards,
Charter.
