What does Dynamic Stability refer to in an aircraft?

Dynamic stability in an aircraft refers primarily to how an aircraft behaves after it experiences a disturbance, such as turbulence or control surface deflection. It specifically relates to the tendency of the aircraft to return to a state of equilibrium—typically straight and level flight—over time after being disturbed.

When an aircraft is dynamically stable, any deviation from its flight path will result in forces that eventually bring it back to its original position or flight path. This means that if the aircraft is disturbed, it will oscillate but gradually settle back to its initial conditions. This characteristic is crucial for pilot control and recovery from disturbances, ensuring safe and stable flight.

The other options presented touch on various important aspects of flight performance but do not accurately define dynamic stability. Speed stability is concerned with the aircraft's ability to maintain or adjust its speed, while maintaining altitude is related to vertical stability rather than dynamic stability specifically. The capacity to respond to control inputs pertains to control response and maneuverability rather than the concept of stability after being disturbed.