Airbus whips out a whopping six aircraft per month on the 220. Boeing even with the restrictions that the FAA recently put on them pumps out 35 a month on the max. Airbus is to up the production to 15 a month by 2025. SWA isn't going to buy two airlines to get maybe half those a month. And buying those carriers, with all the other issues that it brings, just doesn't make economic sense.