What is one key characteristic of a stable aircraft?

A stable aircraft is designed to maintain its desired flight path with minimal control input from the pilot. This characteristic is crucial for easing the piloting demands and enhancing safety, particularly in various flight conditions. Stability in an aircraft often means that if it deviates slightly from its set course or pitch, it will naturally tend to return to its original position without significant input.

When considering the other characteristics mentioned, performing acrobatic maneuvers is typically associated with aircraft that are more agile rather than stable. Concentrating all weight at the tail would lead to instability, as it would negatively affect the balance and center of gravity, making it more difficult to control. Finally, while reaching maximum speed quickly may indicate a powerful aircraft, it doesn't relate to stability; instead, it may produce issues during flight handling. Thus, the primary feature defining a stable aircraft is its ability to maintain level flight with minimal pilot input, reinforcing the importance of design in ensuring safety and control during operation.