In a lot of European airports you're not asked for ID. At least as long as you don't leave the Schengen area. This certainly applies for Zurich, Vienna, Düssel

In a lot of European airports you're not asked for ID. At least as long as you don't leave the Schengen area. This certainly applies for Zurich, Vienna, Düsseldorf and Warsaw. You just scan your bording pass, or barcode on the phone and enter through an automated gate. Same, mostly applies, when you enter the plane. This is not a recommendation not to carry an id, because there's always the possibility that some official, or airline staff wants to see it.