I have traveled via air thrice with a handgun and the first time was a little strange but after that it was o big deal. The airline employee assumes that you are an leo. Denver is kind of stupid because you have to go to a central location for TSA to x-ray your bag. In Houston they have an x-ray machine near the ticketing counter.

I bought a hard case from Midway USA. It was $30+ and has a 4-digit combination lock. I can put two pistols or one with extra mags in it. I put the ammo in original packaging in the suitcase near the pistol case. I have a specific box of ammo that I use for flights.

United has a 1st class desk that is specific for declaring firearms in the West Terminal.