The interaction between elastic aircraft parts and the air they pass through, which can cause the structural failure of said parts.

Aeroelasticity refers to the interaction of a flexible, elastic object (such as an aircraft , , or ) with a flowing stream of air. This can cause various parts of an aircraft to oscillate, or ; if left undamped, these oscillations can quickly grow to a magnitude sufficient to cause a structural failure of the part(s) in question.

Another important aeroelastic effect is , where the aerodynamic forces generated by extending one or more are sufficient to twist the wing or stabilizer on which the control surface(s) are mounted, resulting in the aircraft turning in the direction opposite to that intended.