Folks - it isn't the HR person that has a problem with tats. I know HR people are usually stiffs, but seriously, they aren't the problem - it's the flying public. The HR or pilot interviewer frowns on visible tattoos because the general public may get the wrong impression. We want to instill confidence and professionalism, hence the covering policies. I don't know of an airline that doesn't have the covering policy - and also that really gives a hoot if you have a tat or not....
as long as the public doesn't see it.
Personally, when I would discover an applicant had a tattoo I was fascinated and curious. I'm too chicken to get one myself (don't like pain, thank you) but always wanted to see it, and yes, it became a topic of conversation. Never did it have anything to do with the applicant's skill level or competitiveness (unless it was visible and unable to be covered.)
Get the tat! Just make sure it can be covered or hidden when you're at work.