Let's be realistic, we'd all be very shocked if BA came to MAN themselves.
The sensible way would be to see if AA could plug gaps to their hubs, as in BOS, DFW, MIA possibly LAX, with greater tie in with BE at this end.
If BA did try themselves then possibly MCO would be for them, but again it'd take a massive turn around in their policy to come back to Ringway.
Be interesting to see who makes the next move...