Dress for Success
This topic often arises during interview preps but should be the least of your worries. There are a lot of theories about power ties, navy vs black suit, pleated vs straight leg…none of it matters. What does matter is that you look professional and fit the image the public expects an airline pilot to look like.
Any suit conservative in style is fine. There is no need to spend $$ on a new suit unless it gives you confidence. However, it is important that it fits. Put on a few pounds since you last interviewed several years ago? Try it on and have tailored if necessary. Make sure your shirt is pressed and shoes are polished. Bring an extra shirt just in case you spill some coffee enroute. The tie should be conservative in style. Don't try and make a statement with something loud. If in doubt, check the airline uniform and go with similar style. You want them to picture you wearing their uniform!
Make sure you are well groomed. If necessary, use a professional to trim those eyebrows and tend your nails. Avoid excess jewelry such as multiple rings and union pins. Lastly, bring a few breath mints and protein bar. You may wait several hours for your turn at the panel and don't need the distraction of an empty stomach.
You can explain how important image is during the interview but your presentation speaks volumes.