Is there actually an official ranking structure for pilots? Just interested as I had always assumed it was something like this (seems similar to fire fighters and special constables rank insignia):
Captain / PIC: 4 bars
First Officer / Co-pilot: 3 bars
Second officer / Trainee?: 2 bars
Pilot in training: 1 bar
I'm not sure about 1-2 bars, what do these actually signify? and are they even used at all?