What is a desirable characteristic of an airplane with good longitudinal stability?

A desirable characteristic of an airplane with good longitudinal stability is a minimal tendency to pitch. Longitudinal stability primarily relates to how well the aircraft maintains its attitude along the pitch axis. When an airplane has good longitudinal stability, it means that any disturbances causing changes in pitch—such as turbulence or changes in weight—are effectively countered by the aircraft's inherent design. This allows the airplane to return to its original flight attitude without excessive pilot input.

In this context, the airplane's design features, such as the placement of the center of gravity relative to the aerodynamic center, contribute to a stable pitch behavior. An aircraft with minimal pitch tendency helps ensure a comfortable flying experience, as it minimizes excessive nose-up or nose-down attitudes during flight. Thus, a slight upset in attitude will return to level flight without dramatic movements, enhancing overall flight safety and handling.