It's not quite accurate to say that a "symmetry" helps something fly. While symmetry is important for flight, it's not the direct cause. Here's a more accurate breakdown:

* Symmetry and Aerodynamics: A symmetrical shape in an aircraft (or bird) helps with stability and balance. This is because the air resistance is equal on both sides, preventing the aircraft from tilting or spinning uncontrollably.

* Aerofoil (Wing) Shape: The key to flight lies in the airfoil shape of a wing. This shape, which is *not* symmetrical, creates lift.

* Camber: Wings are slightly curved on top, this is called camber. This curvature means the air flowing over the top of the wing has to travel further, therefore moving faster.

* Bernoulli's Principle: The faster-moving air creates lower pressure on the top of the wing, while the slower-moving air on the bottom creates higher pressure. This difference in pressure creates the upward force, or lift.

So, how does symmetry play a role?

* Stability in Roll: A symmetrical wing shape, especially in the cross-section, helps prevent the aircraft from rolling uncontrollably.

* Stability in Pitch: A symmetrical wing shape (along the length) helps the aircraft stay level and prevents pitching up or down.

In summary: Symmetry is crucial for stability during flight, but the actual lift that allows an aircraft to fly comes from the asymmetrical shape of the wing, which is designed to create a difference in air pressure above and below.