When maintaining a constant power setting during a climb, how can airspeed be altered?

When maintaining a constant power setting during a climb, altering airspeed effectively requires changing the pitch of the aircraft. By increasing pitch, the nose of the aircraft is raised, which decreases the airflow over the wings, thereby reducing lift and causing the airspeed to decrease. Conversely, lowering the pitch will cause the nose to drop, increasing the airflow over the wings and increasing lift, which in turn increases the airspeed. This relationship between pitch and airspeed is fundamental to controlling the aircraft's performance during different phases of flight.

The other methods such as adjusting the throttle focus on power management rather than airspeed control since the power setting remains constant. Using elevator trim, while helpful for alleviating pilot workload in maintaining a desired pitch attitude, does not directly change the airspeed if the power setting is constant. Lastly, rolling the aircraft primarily affects its roll axis and is not a method that can directly change airspeed during a climb while holding power steady. Therefore, pitch adjustment is the primary and effective means to alter airspeed in this scenario.