A neat story I came across along with some vintage posters from the early 1900's and 1940's.

During World War I and again during World War II, the American Red Cross launched nationwide, volunteer-driven knitting campaigns to supply soldiers and war refugees with warm clothing. These volunteer knitters belonged to a Red Cross unit called the Production Corps that also produced bandages and sewn garments (such as pajamas) for veterans and civilian hospitals.

For more information on the rest of the story as well as some vintage knitting patterns of some of the listed items above along with sweaters, scarves and socks here.