One of my clients has super long, super thick, super curly, super gorgeous hair and she shared a fantastic trick she uses for keeping her curls from frizzing out in the process of drying naturally.
All you need is an old T-shirt. The neck should be snugg enough that if you pull it up around your head like a headband it will stay there. (I know, this sounds like you're going to look ridiculous but it's genius so just do it.) So you've washed your hair. Toweled dried. And now the best way to get your natural curls to dry without turning them into cotton candy fluff is to not move at all, definitely not outside where a gentle breeze could possibly disturb the surface of your hair and dry the outside to quickly so that it separates and creates a huge halo of fly aways. So you take an old T-shirt, put it on as you normally would except don't put your arms through the sleeves. Pull it back halfway over your head and keep the neckhole in headband position. Pick up the bottom of the shirt and put your hair inside it like a bag. The next part is dependant upon what type of curls you have an how much hair you have and how big the shirt is. If you have super thick, super long hair that fills up the shir then I think you can just leave it as it is, with the bottom of the shirt hanging down like you're pretending to be a nun (for whatever reason you might do that...). If you have shorter and/or less thick hair, a bigger T-shirt or simply more delicate curls that lose volume and bounce due to being weighed down when wet you'll want to kind of pile your hair up on top of your head and tie off the shirt to create something like a cotton shower cap. Now your hair is in a breathable bubble, contained and protected from drying unevenly and looking flat and frizzy!