Question:
Suppose that a plane takes off from an airbase with a CAP mission over it, is patrol attacked and gets an R result. Where can that plane return to? Does it have to go back to the base it started from? Is this true of all R results?

Answer:
The air unit “returns” to any friendly airbase within mission range, with a capacity greater than 0 — just like any other return result. Air units are never required to return to any particular airbase, not even the one they initiated the mission from.

Source:
TEM 74