If you're still looking for fabrics. I've found some materials by doing some searching.
The flightsuit is made from: Cotton Twill.
The Flak jacket is from this "Tackle Twill" I did some digging, and it's also referred to as Poly-Pro Twill. Otherwise known as Poly-Cottn Twill which gives the cotton a poly blend, creating the sheen. It's used for lining curtains, and easily sourced. You can buy both heavy duty and light weight versions of the fabric.