Originally Posted by
First_Principal
It seems to me the answer is in the many AAIB etc reports that I've read where the driver is referred to as the aircraft commander.
Taking a leaf from the senior service for a moment, we find that a commander is a person capable of navigating and commanding a ship of small to middling size. A commander gets three rings.
A captain on the other hand is the person who is experienced enough to get to play around with bigger vessels. He or she gets an extra ring.
So, if you must, perhaps your average <5700kg spamcan driver could claim 3 bars, on the other side of that maybe you get an extra one...
No, not really. The term "commander" is simply used to describe the person in charge of the vessel. It does not imply that the commander should have any particular title or wear bars. Titles and uniforms are used by organisations employing or appointing people to a role. Think "Barista" or the KFC uniform. Except perhaps in the military, those titles or uniforms have no legal significance.
The
role of being in charge of an aircraft or vessel does have legal implications, as we all know, but not the title or uniform.
Nothing to stop individuals conferring a title or uniform on themselves, of course.
As a fellow pilot's (ex) girlfriend put it, there's really no need for a private pilot to wear a uniform: "Never ask a man if he's a pilot. If he is, he'll soon tell you."