Some countries and airlines require pilots to submit to breath tests as part of reporting for work, while other countries use hair samples for drug testing in addition to urine.
Let's be clear about something, regardless of gender, airline pilot is not the type of job to make statements or express one's individuality. This is why there are strictly enforced uniform policies. Most female pilots in fact do and can wear whatever they'd like. I often have my nails done.
Males and females are required to not have any tattoos visible when in uniform. If you can cover them up with your uniform (and for the interview) you should be fine. The caveat to this is that typically pilots wear short sleeve shirts during the summer.
Ear piercings are generally allowed for both flight attendants and pilots. However, each airline may have its own policy on piercings, so it is advisable to check with the specific airline.
Yes, some airline pilots do carry guns in the cockpit but carry a gun lawfully they must belong to a special program called the Federal Flight Deck Officers (FFDOs). This program requires special training and pilots who enroll have strict limitations on when they can use the firearm.
And because drug tests can't tell the difference between THC and CBD, pilots who are suspected of using THC, accidentally through CBD or otherwise, can be subject to certificate revocation while a positive drug test following an accident could even jeopardize insurance coverage.
According to The May 2021 Occupational Outlook Handbook, the Bureau of Labor Statistics, the salary for commercial pilots is $99,640 per year. The median annual wage for airline pilots, copilots and flight engineers is $202,180.