SNIP
As regards wear of Spun Silk v. Cotton I can only refer to our A-2 linings, over the years we've see more/worse damage to the neck area of Spun Silk lined jackets than we see in the cotton lined jackets. SNIP.
Hopefully Marc can shed more light on the letter,
"the use of silk in flying jackets had been discontinued"
Here's a question for those with more expertise on "pre 1939 non leather USAC flight Jackets" than I have.............How many and which used Silk in their manufacture? I can't imagine any use other than for lining but I'm very willing to be corrected