From The Truth About Guns:

My first advice to traveling gun owners is to always be nice. A good attitude goes a surprisingly long way in getting you through problem situations. Do your homework, know the rules for checked baggage (no loaded firearms, ammo in a separate container) , and destination gun laws concerning possession of firearms (i.e., concealed carry no-go zones, magazine limits, etc.) pack well and leave early, check-in early and then…smile. I may know TSA’s rules and regs more than anyone at the airport, but I don’t flaunt it or shove it in their faces.