What results in the best endurance on a jet aircraft?

The best endurance on a jet aircraft is achieved when operating in the lift-to-drag maximum configuration. This configuration minimizes the drag on the aircraft while maximizing lift, allowing it to stay aloft for an extended period using minimal fuel.

When an aircraft is in the L/D max configuration, it can maintain a balance between lift and drag, effectively optimizing its flight path for endurance. In practical terms, this often means flying at a specific airspeed that allows the aircraft to maximize its range, which directly correlates to how long it can sustain flight before exhausting its fuel supply.

In contrast, high power settings typically result in increased fuel consumption, thus reducing endurance. Furthermore, being at max fuel does not necessarily equate to optimal endurance, as it pertains more to the weight rather than the aerodynamic efficiency needed for longer flight times. Finally, a high angle of attack usually leads to increased drag and can be a limiting factor in maintaining level flight, which negatively impacts endurance.