What do the letters "VFR" stand for?

The term "VFR" stands for Visual Flight Rules. This set of regulations governs the operation of aircraft in weather conditions generally clear enough for pilots to see where the aircraft is going and to maintain visual references to the ground and other navigational aids. Under VFR, pilots are responsible for maintaining separation from other aircraft, as well as navigating visually rather than relying solely on instruments.

Using VFR is essential for pilots flying in good weather conditions where visibility is high, allowing them to orient themselves and navigate effectively. The rules provide guidance on minimum visibility and cloud clearance requirements, which varies based on the terrain and airspace in which the aircraft is operating. Understanding VFR is critical for pilots as it influences flight planning, safety protocols and operational procedures.

Other options like Variable Flight Rules, Verified Flight Regulations, and Vertical Flight Route do not reflect established aviation terminology and thus aren't applicable to VFR's context within aviation.