So, you just stroll in and get in line at the ticket counter?
Yep, that's right.
It's really not that big of a deal to fly with firearms. CBK outlined it real well what you need to do to fly with firearms. Basically you just gotta tell them, have them check it, keep ammo seperate from the firearm, and get on the plane.
If this is a black powder firearm you can not take loose powder onto the airline. You must purchase new powder at your destination and then leave it there.
Also you can not carry the ammunition in you carry on luggage. It must also be checked at the ticket counter.
In addition to locking the case with pad locks I like to either strap it closed or duct tape it closed on both ends just in case the latches pop open.