Hahahaha
I got told by my flying instructor early on in my PPL to get rid of my safety pins in my ear - not because of my perceived image problem but because they were ripping holes in the student headsets!
I still have a secret love of punk rock and you know what - as soon as I get another few years of this long haul big jet money I'm going to jack the whole lot in and move to fiji, start my own float plane company where I will undoubtedly wear hawaiian shirts, flip flops and probably pierced ears as well. And I'll give any wannabe who turns up dressed accordingly, a job on the spot
But sadly, for as long as I want to continue working for my present employer - or get a job with 99% of the other decent airlines on this planet - then yes it's true that earrings, tattoos, excessively wacky hairstyles etc are a definite no no.