What should remain constant when flying straight and level?

When flying straight and level, maintaining constant altitude is crucial. This involves keeping the aircraft at a predetermined height above the ground or sea level without climbing or descending. Altitude is a fundamental aspect of flight that affects various performance factors, including navigation, safety, and compliance with air traffic control regulations. Maintaining a constant altitude ensures effective communication with ATC and adherence to airspace restrictions, while also providing a stable flying environment that contributes to passenger comfort and aircraft performance.

In straight and level flight, pilots may also note that airspeed, bank angle, and pitch attitude can change depending on various factors, including wind conditions and flight maneuvers. For example, airspeed might vary due to changes in power settings or atmospheric conditions, while bank angle could be adjusted for turning or maintaining controlled flight under diverse situations. Pitch attitude, which refers to the angle of the aircraft's nose relative to the horizon, can also be altered to adjust airspeed or coping with turbulence. Therefore, while these other factors are important, they do not remain constant in the same way that altitude does when the aircraft is flying straight and level.