Pressure and friction, the eternal pair that is resistance.
All inhabitants of our planet Earth lived and evolved in fluids: birds fly in air, fish swim in water. Exactly for this reason, nature shaped their bodies to minimize resistance as they move in fluids: they pierce them with pointy faces to reduce pressure, while their feathers and scales reduce friction. No surprise, then, that our planes and ships follow the same design: nature has always been an endless source of inspiration.
Why do fish have their characteristic shape?
Why do golf balls have dimples?