As above, but always check with the airline in both your departure and your arrival airports. True story: We visited TN from ID a couple of times before moving here. Flew SW Airlines both times. Called SW in ID found out what I needed. Was a very smooth process. Declare CCW, get tagged at counter, over to TSA desk, cleared, and on the way. Didn't think to talk to SW in Nashville though. Spend my 2 weeks in TN and go to the airport to return home. SW agent there rejects the very same box/lock setup I flew in with. Was all legit per TSA but the counter lady would have none of it. Asked to speak with TSA and was told they are in the back and will not come up front unlike ID where you go to a TSA counter for clearance. SW ticket counter refused to let me clear my CCW. Luckily, my buddy who we visited was hanging out so I sent the CCW home with him and got on the plane. What would I have done if he wasn't there? Toss the gun in the trash, hand it to the closest thug I could find? The counter people could care less what TSA rules you show them, it is all based on thier own mood/interpretation at the time.