What does the term "best lift/drag ratio" indicate?

The term "best lift/drag ratio" indicates the effectiveness of the aircraft's design in maximizing aerodynamic performance. This ratio is a critical measure of how efficiently an aircraft generates lift relative to the drag it experiences during flight. A high lift/drag ratio means that the aircraft can produce significant lift with relatively low drag, which allows it to maintain altitude or climb while consuming less power or fuel. In practical terms, aircraft designed with optimal aerodynamic shapes—like gliders or modern airliners—achieve a higher lift/drag ratio, leading to better fuel efficiency and enhanced performance during various phases of flight.

This concept is particularly important during cruise, where optimizing lift relative to drag minimizes fuel consumption, and during gliding, where a high lift/drag ratio allows for extended flight distances without engine power. In essence, the lift/drag ratio directly reflects the design characteristics and aerodynamic efficiency of the aircraft.