Flying from MSY to LAS on Spirit went mostly smooth. I had one handgun, a KelTec PR57, in a Pelican V100 lockbox inside another piece of luggage.
The airline agent asked to see the gun even though it was packed inside the luggage, so I opened the lockbox and showed her. Normally that is not part of the process, but if I had checked only the lockbox, as I sometimes do, I would have had to open it at the counter so they could place the declaration form inside. Since this was not too far off from that, there was no reason to cause a scene or ask for a manager just to prove I was right. I fly through these airports every week, often recognize the agents, and always try to be polite. If something was clearly against policy, then I would ask for a manager.
When I landed, my bag came out on the carousel like normal. TSA had inspected the luggage, but they had not touched the lockbox or broken the non-TSA locks. Everything was secure, and I was on my way.
My only experience flying with a sidearm was in 2012 when my son & I flew MCI-LAS to what was then FrontSight. The Southwest gate agent was obviously trained on the subject, as when I presented our luggage & declared our firearms, she said ‘show me that they’re clear & safe’. She watched us open the cases, rack the slides, she signed off on the cards, put it in the cases, watched us lock them & replace them in our luggage. Complete smooth non-issue.
Only glitch came on the way back when we had empty brass in a plastic bag. As ‘ammunition’ has to be in appropriate boxes, TSA pitched a fit. My argument was that empty brass is no longer ammunition, and, after summoning the TSA supervisor, he agreed, stated that it was the same as scrap metal, and sent the bag on through.