Assuming the Airbase is Friendly as you say, they SHOULD land. Sometimes, though the AI including wingmen fly quite a distance away to set up an approach for landing. If you watch them LONG enough they will probably land.
On the other hand, I am not sure that they will actually RTB to a land base that they took off from (other than the carrier). If you land at a base, or program a landing at a base, they should land. If you took off from a Carrier, RTB will send them back. If you land on a different base, they SHOULD (eventually) follow you there.