TexasCHLforum.com

Search this site for "airline gun." Many threads on this.

Also, the exact federal law/TSA rules can be found on the TSA website (TSA.gov I think). Be sure to read the specific policy of the airline on their website.

Basic answer -- the gun must be unloaded and in a hard sided, locked case that only you have the key or combo to. NOT a TSA approved luggage lock. You can put the hard sided gun case inside your regular suit case (which is what I do).

I use a plastic handgun case with foam padding that I got at a gun store for $5, and use a key lock that fits around the handles.
You can buy more expensive cases that are harder to break into, but I figure that will get stolen as well if some baggage handler roots through my suitcase. I would think that a hard-sided suitcase would work just as well as long as you could lock it.

There is no "TSA approved" gun case that I am aware of, just the requirement for it to be a hard case and be locked with only you having the key or combo.