Last FAPA Aero I went to in LAS, 95% of guys were no tie... I think its good to try and stand out, but when the website clearly says save the suit for the interview, I do as I am told. I will let my resume and personality or lack there of do the rest. I would make sure you eat before hand and wear comfortable shoes. I made the mistake of doing neither in LAS and recall how miserable the hour wait for UA was.