Originally Posted by johan rebel
I read an article in the Swedish press a while back, in which a spokesman of the Arlanda (STO) police force said that they were constantly reminding the airlines that passengers do not need a passport or national ID card when traveling withing the Schengen area. Apparently passengers without passports were being sent to the police to apply for emergency passports by check-in staff, much to the annoyance of the cops.
I am 99.99% certain that everybody needs a valid proof of citizenship when crossing an intra-Schengen border, with the possible exception of the travel within the Nordic countries where there has been passport-free travel for many, many years. I once arrived at Copenhagen and the lady in front of me at passport control just said something like "Danske fra Sverige" (sp?) and was waved through.
But I also know that in Amsterdam the immigration police do sometimes do spot-checks on intra-Schengen flights at the arrival gate (it happened once after a flight I was on from Paris) and all passengers have to present proof of citizenship.