> You don't normally need to show your passport or ID when crossing the internal borders of the Schengen area. However, all Schengen area countries (see below) are allowed to reintroduce temporary border controls in extraordinary circumstances, for example, in case of a threat to public policy or national security.
This is not about borders. It is about the rules of the air company. Any place where the ticket is nominal can (and in my opinion should) ask for an ID. At least to prevent for example people hording tickets and reselling them.
Sure, but in your comment above you claimed that this is already the case for all flights in Europe, which is just not true and different from your opinion that this is what ought to be happening.
Also if the security at the airport works, why would they need to see your ID anyway?
Edit: see here https://europa.eu/youreurope/citizens/travel/entry-exit/eu-c... :
> When do I need to show a passport or ID card?
> You don't normally need to show your passport or ID when crossing the internal borders of the Schengen area. However, all Schengen area countries (see below) are allowed to reintroduce temporary border controls in extraordinary circumstances, for example, in case of a threat to public policy or national security.