Photo copies of the original manuals for Airstream products are available from Secretarial Services. The contact information found below is quoted from the Vintage Airstream Club web site's Frequently Asked Question Section:
Q: I need an owners and service manual for my Airstream. Where can I get one?
A: The first owners manuals were published in 1964. Prior to that, the owner received a brown envelope containing parts lists and other helpful information on the accessories in his trailer. The VAC has started making these available in the Members Archive section. A service manual with instructions for performing service operations did not exist until 1972.
You can get photocopies of owners manual (1964+) and service manuals (1972-1986) from:
Helen Davis Secretarial Services
PO Box 484 Sidney, OH 45365
Prices are about $33 and $70 respectively. After 1986 the Owners Manuals included available service information
Original manuals are ocassionally advertised on the Vintage Airstream Club Classifieds, some have been offered on Airstreamforums, and it is not uncommon to find them listed on E-Bay.
Good Luck with your search!