I recently flew from the Netherlands to Italy. The outbound flight, done with Ryanair, I had to provide my document number when checking in, and also to show my document while boarding the plane.
On the inbound flight, done with Transavia, I could check in without providing any document detail, and also boarding was only done by checking the boarding pass.
Doesn't the second operator potentially allow to board also with fake identities? Is this really allowed?