I was researching both classic Avions and Airstreams for about 6 months before picking up a '63 Avion T-20. It was in my price range, and more importantly it was at a dealership 5 miles away from my driveway. So that beat driving 3 states away.
The frame, running gear, construction and the fit & finish remind me of my 69 Volvo, but perhaps lighter.
The Avions dont have the name recognition that the Airstreams do.
The upside of this is that you can get into a unit for 1/3 to 1/2 the price.
The downside is that there are not as many resourced catering to classic Avion restoration. Unless Inland Andy has an evil twin that I dont know about
Anyhoo, the 2 best sites Ive found out there for the Avions are as follows:
http://www.silveravion.com/
Has historical information, manuals, brocures and tech tips going back to the beginning.
http://my.execpc.com/%7Edrg/avion.html
Is the Unoficial Fleetwood Calvacade club of Indiana and provides a wealth of information for classic and newer avions, as well as classified, repairs and tech talk.
Both sites have the business address for Cayo Repair service who still manufacture parts for all years of units.
Aside from the running gear windows, and body, most of the parts where, and still are off the shelf so are generaly as available for one as for the other.
Note I did say MOST. So if anyone knows where I can get my hands on a mushroom cap for the bathroom vent for a '60s Avion, you'll be my new best friend