Seems to me most of what you would need done in any Airstream could be done by any good local RV technician if you are not near an Airstream dealer. Body work or getting to anything under the body work, like holding tanks, seems to be worth a special trip to the Airstream dealer.
In our Airstream, it looks like the appliances, and the plumbing, heating, AC and power equipment are all name brand from established RV suppliers, like would be found in many other trailer brands. The wiring, piping and electrical all looks hand built with standard fittings, as did all the the other trailer brands I looked at. So, all stuff a good RV tech could deal with.
Finding a good RV tech - now that is a whole other story