Flying within a country is different from crossing international borders. Even within Schengen many (most?) countries still require visitors to be holding a valid travel document (passport or ID card). Random spot-checks are often carried out close to borders (although by local police, rather than immigration or border guards).
I'd certainly be interested in discovering whether airlines are required to confirm that passengers have these.
Many airlines now also require 'official' ID for flights even within a country, but AIUI that's purely airline policy rather than a legal requirement.
I've actually been checked in Holland by customs when coming home from a Schengen country.
He asked me to show an ID, I asked "why?", and he just responded "Because I say so". I was a bit too flabbergasted and not prepared for that answer and just showed him. He then proceeded to someone else who was even requested to come to the counter and let his bags get checked.
I'm curious whether I was actually required to do so.
The problem is that in the Netherlands there now is a law requiring you to show an ID if the cops ask for it.
However, this was allowed with the provision that the cops had a sensible reason for doing so, i.e. you broke the law, or you were doing something suspicious.
I see no reason why it is any of the cops business to know who I am when I'm just walking down the street.
Same situation applies at the border, there is a seperate section for Schengen countries in the Amsterdam airport and you normally get in and out without showing an ID. I see no reason why it suddenly is any business to the customs officer to see who I am.
I think he's talking about the gates that handle flights to/from Schengen countries being in a different part of the airport, before passport control. The assumption is that once you're in Schengen the border guards at the first entry point should have ensured you're allowed to be there.
However, in every airport where I've seen that, I've certainly been able to get as far as the gate without ID (particularly if I've a pre-printed boarding pass), but I've always needed either a passport or EU member state ID card to actually get on the plane.
If you can get on without your ID, however, there are generally no checks at all at the far end.
Ah, OK, this makes sense. I admit that I don't think much about immigration or customs when I am arriving in Europe because it is all so simple. It's only when arriving in the US that I dread the experience. (And I am a natural-born US citizen.)
There is nothing "international", technically, about flying within the Schengen zone. Airlines don't require you to produce an ID because you're flying "internationally"; you need an ID to board a plane anywhere in the EU/EEA, also for "domestic" flights.
I'd certainly be interested in discovering whether airlines are required to confirm that passengers have these.
Many airlines now also require 'official' ID for flights even within a country, but AIUI that's purely airline policy rather than a legal requirement.