Here is a link to a great
video about transporting firearms by air.
It was posted to the "Discussion" forum recently.
The video is actually from a computer-related conference since hardcore computer geeks have evidently discovered that traveling with firearms allows them to hard-lock their expensive and/or high-security tech gear in the same container. However, the guy giving the presentation is extremely knowledgeable and experienced, he obviously likes firearms, and all of the advice seems legally sound.
The video has brief NSFW content- several 4-letter words and a brief sexual reference. Consider yourself warned.