Your Airstream dealer will sell and install a hitch for you. Most likely, they have a "preferred" brand/model that they like to sell, which may or may not be the best solution for you. Do your homework and decide on the best hitch for your situation. Then ask the dealer to install your choice, as the service department won't care either way. You may, however, end up paying a lot more for them to do this.
When I purchased my new trailer last year, the dealer "threw in" a hitch and installation as part of the deal. I wanted to go in a different direction, so I had a ProPride hitch drop-shipped to the dealer and they had it installed and waiting for me when I showed up for delivery. I was given a credit on my sales order for the hitch that I didn't take.
2019 Flying Cloud 30FBB
Bunkhouse is sold...something more "classical" on order!
2020 GMC 3500HD Duramax AT4
ProPride 3P w/ 1400 lb. spring bars