In all flights on commercial airlines I have done so far, associating a name with the ticket and showing an identification document at security and boarding has been mandatory, even if the flight is domestic and there are no border-crossing procedures involved.
In Europe, it is still possible to buy a long-distance train ticket anonymously and travel using it without any identity checks, depending on the country - Switzerland for instance. This type of ticket is transferable and no one knows the name of the traveler at the end.
Do any commercial flights exist that can be boarded anonymously in the same way?