(Newbie here for this board. Some of you may recognize me. I apologize in advance

.)
Just did CLE to DFW and back again. CLE went as smoothly as could be expected. Countergal at DFW forgot the declaration card. When I reminded her, she couldn't find them. Fortunately, whoever she called knew where they were. That was the second-worst problem.
1. Take a gun you don't mind losing.
2. Put it in a lockable case; secured with one or more
key type locks. You don't want the TSA folks or anybody else to know the combination to your gun box. Unloaded, action open if possible. Unloaded magazines may also be carried in that box. Some airlines will let you carry loaded magazines, some won't. Don't tempt fate. The counter crew should either ask you to verbally certify that the gun is unloaded, or actually ask to see it. (Nobody did at either airport.)
3. Put the gun case in a lockable suitcase. Use a TSA lock for the lockable case. AFAIK, it doesn't have to be a hard-sided case. Put the declaration card in the lockable suitcase and secure it when told that they're done. The TSA may still open the case, but they are only supposed to open the gun box in your presence.
4. Ammunition - should be in a box of some sort, not loose. There's some argument about whether loaded magazines are acceptable. Some airlines seem to think that you should put the ammunition in a separate suitcase, but this didn't come up (American Eagle).
That was that except that TSA opened my outer bag on the return trip and opened the ammunition box. I really don't appreciate strangers pawing through my undies, but I really didn't like 'em mucking with the ammunition because I'd rubber-banded the outside of the "factory" box and put the whole thing in a plastic bag to avoid any "loose ammunition" issues. The TSA folks just tossed the bag, rubber band, and ammunition box back into the suitcase.... Minor but important affront....
Overall, NBD, and being from OH it was nice to be able to carry in a restaurant where the "gunbuster" sign read "you gotta have a license"....
A family member asked me why I bothered. "Because I can!" and, "to pave the way for others...."
Our flight back from DFW was delayed for about four hours. I spent much of that falling in love with a waitress at a "Friday's". (The wife was not amused.) Then time to get shoehorned into an "CRJ", which is sort of a schoolbus with wings, and somewhat less comfortable when your femurs are about 3/8" too long for the seat.... I'm not going to try that again anytime soon.
Regards,