Except for members of certain ethnic groups (Italians, Hispanics), most American women before Vatican II wore hats to church. Just like most of their foremothers (depending on the country) all the way back through the Middle Ages. Hennins were hats too, so that works out logically enough.
So why did American Catholic women cease wearing hats to church and begin wearing veils and chapel caps and suchlike, in the years immediately running up toward Vatican II? What is the mysterious X-factor, I asked the older ladies in choir? And lo, I was answered.
Yes, children, that’s the sordid truth. (At least, as sorted out by oral history agreed upon by the older choir ladies and my mom.) Women and girls all across America (and all across Europe, probably) stopped wearing hats and started wearing mantillas — because hats messed up their beehive hair.
But of course, veils still messed up their hair somewhat. So gradually, the wearing of veils in such cases led to the impatience with all haircoverings whatsoever.
Big hair is the hidden hand, people. Fear the perm!