What is the definition of "vertical separation" in aviation?

Vertical separation in aviation refers specifically to the maintenance of a safe altitude difference between aircraft in flight to prevent collisions. This is a critical safety measure employed by air traffic control and in operational flight practices to ensure that aircraft can operate in the same airspace without the risk of coming too close vertically.

This concept is essential for maintaining safe flight operations, especially in conditions where multiple aircraft may be in close proximity, such as during takeoff and landing phases or within busy air corridors. The standard altitude separation criteria, often expressed in feet, ensures that aircraft remain safely apart, allowing for safe maneuverability and error margins.

For clarity on other options: the distance between two aircraft on the same runway is more about horizontal spacing rather than vertical separation, while the height difference during takeoff does not typically pertain to separation standards in the airspace. Lastly, the separation between the aircraft and obstacles on approach focuses on flight safety concerning terrain and obstacles rather than separating aircraft from one another.