[Hnrobert42]

You do not need a passport although you can use one. A driver’s license or other government issued ID is sufficient. It may even be possible to fly without an ID, like if it was stolen or lost, but it would be a holy mess. The comedian Hannibal Burress has a funny bit about it.

[withinboredom]

In Kentucky (at least back in the day), several people who knew you a long time, vouching for your identity was all that was required to be that person. I wonder if anyone ever tried it to get on a flight?

[ryanlol]

You can travel without any ID just fine, evidence of EU (or EEA?) citizenship is sufficient.

[Kbelicius]

Wouldn't evidence of EU citizenship be and id or can you get a document that says that the carrier of the document is an EU citizen without any identifying information about the carrier?