What is one primary requirement for flying under Visual Flight Rules (VFR)?

Flying under Visual Flight Rules (VFR) primarily requires that pilots maintain visual contact with the ground as well as with other aircraft. This ability to see and avoid other aircraft, terrain, and obstacles is fundamental to VFR flight. It allows pilots to navigate using visual references rather than relying solely on instruments. The requirement for maintaining visual contact is crucial for ensuring safety and situational awareness in conditions where visibility allows for such navigational techniques.

While flying above 10,000 feet, filing flight plans, and using autopilot can be factors in flight operations, they are not primary requirements specific to VFR. For instance, VFR can be conducted at various altitudes and does not inherently require the filing of a flight plan, although it is good practice and may be required in certain airspace. Autopilot use is also not a requirement under VFR; pilots can choose to operate the aircraft manually. Therefore, maintaining visual contact with the ground is the key requirement that allows pilots to operate safely under VFR.