Hi all,
Understandably A-B-C-B-A routing has been banned a while back. It would allow a out of base "hub" without all of the associated penalties and ruin the game for players in medium bases.
However it makes no sense if A and C are base airports. For example, I fly from BOG and CLO (amongst others) in GW4 and would like to serve MAD from both airports. Unfortunately CLO has insufficient demand for such a route.
In the spirit of the game, my airline would certainly be allowed to fly this sector. However economics make this difficult to justify.
I think this would open a lot of options for players with smaller bases. Base set up costs are still a thing and this would be mostly interesting for airlines flying from somewhat limited countries... (E.g. Colombia)
Cheers,
NC