No comment on tattoos, but rings are a different matter. Rings and aircraft (the type you have to clamber in and out of as opposed to those you stroll into off an airbridge) just dont mix. Shortly before I joined tankers two guys on the line had lost fingers in short succession through slipping. We had a rule, no rings when you were flying or working on aircraft, nothing to do with fashion, everything to do with not losing a finger.