What is the required plane change necessary to arrive at a destination called?

The term that best describes the required plane change necessary to arrive at a destination is "connection." A connection occurs when a passenger has to change planes during their journey to reach their final destination. This may involve transferring from one flight to another, often at a hub airport, and it signifies that the flight itinerary includes multiple legs of travel that are linked together. Connections are essential in air travel, especially when there is no direct flight available to a specific destination.

In contrast, while terms like transfer, changeover, and layover may seem related, they generally refer to different aspects of travel. A transfer often implies moving from one mode of transportation to another, a changeover indicates a switch that may not necessarily be flight-related, and a layover usually refers to a waiting period at an airport between flights rather than the act of changing planes itself. Thus, in terms of specifically naming the required plane change, "connection" is the most appropriate and accurate term.