Jose wrote:

btw, there's no such thing as a "trainer runway".

Right. I was thinking small aircraft, and was trying to concisely
distinguish between a short runway and a long runway. In other words, a
student small aircraft pilot isn't going to have the length of a 747
runway.

Student pilots to use regular runways, and mix with regular air
traffic. They just have an instructor aboard until they can handle
that much on their own.