The Plano gun vault or maybe gun gaurd (I cant remember) is what I use when I have to fly to my hunting destination. It was half the price of a pelican and seems to be built just as well. It has been on a dozen flights with me and I have not had an issue with it.
I don’t clean my barrels until I notice accuracy is dropping off. I have noticed since moving from a very dry climate to a very humid climate, the time between cleanings has shortened up a bit. Not sure by how much though.