Cadet caps can be ideal for someone who doesn't have a protective pad of hair on top of their head. Like me. For some reason, I keep hitting the top of my gead on cabinet doors and tree limbs etc. That causes injured scalp. Purchased baseball caps and similar often have no padding for scalp, they have a coarse, rough inside, plus have a button or rivet in the center. Hitting ones head on that feels like being struck with a ball peen hammer, painful and causes skin tear, bleeding, and scab.
A cadet cap has a one piece fabric top. No center rivet or button. By adding a quilted layer to the top, it's protective. A few months ago, I sewed a few flannel cadet caps, with quilted tops. Those are protective and comfortable, and warm. They are also easily washable and can go into the dryer. Flanell does cone out a bit unkempt after laundering. With warmer weather, I wanted some different caps. Something less warm, but durable Nd easy to wash and dry like any other clothing.
I made this one using denim harvested from a pair of thrift store jeans. The lining is quilting cotton, for lightness and absorption and air exchange. However, being heavy denim this cap is still quite warm.
This denim was at the outer limit of thickness and stiffness that my sewing machine and skills can handle. I sewed the quilted top to the inside liner before sewing the liner the outer shell. I was not able to sew in a sweat band. The top is a little lumpy. However, these caps become somewhat form fitting.
I made the bill using the same heavy / semi stiff interfacing as before. It makes a somewhat flexible bill that I like.
During the winter I bought some duck fabric on line. I used that to make a second cap. This time, no hat band. The sides of the liner are the same fabric, and the top of the liner is a sandwich of muslin / thin quilt batting / muslin. The sides also have a thin fusible interfacing for a little stiffness.
I like this cap much better. It's lighter and cooler. I don't care as much for the stitching I added to the top, but maybe that will look better on washing. I have more duck fabric, so might make another without that extra stitching.