I found this US Air Force Academy sweatshirt at the thrift store recently. I'm guessing it's from the 1950's-1960's due to details like the expansion gussets on the sides, the width of the waistband, the look of the tag, and unique way that the body is made. I've looked a little online but haven't found any useful information about it yet though.
What's neat about the body is how it was made. It's just one piece of fabric that is oriented with the grain going horizontal rather than vertical so that the shoulders have no seams.
I've taken measurements and notes about the sweatshirt so that I can try and make one for myself, although sourcing the heavy-weight cotton rib knit fabric for the gusset may be a challenge.