You can't move miles from one program to another, and you would probably do best trying to accumulate miles as much as possible in a single program in the future. DL miles are notoriously hard to redeem, so DL would probably not be a good choice.

As far as your existing miles are concerned, AA permits OW redemptions for half the miles required for RT. If that's true of AC as well (I don't know AC's policies, but its partner UA is the same as AA in this respect), you may be able to draw on both programs to book the equivalent of a RT flight. It's not quite the same as transferring miles, but it is a way to apply miles from two programs to one trip.