NW has plenty of DC9s, Airbus', and 757s getting tans in the desert climates. If they need planes they can get them quickly. They own a lot of those planes, so it isn't a big issue forcing them back into service. As for BNA going to CRJs, that's life these days.

I have absolutely no idea what kind of strategy NW has with BNA, but geez, that's a decent market (aside from the fact that WN serves it) that really doesn't have a truly dominant legacy carrier. NW is in a perfect position there to grab market share considering hub positions and convenience. Even Nissan USA relocated from Torrance to Nashville a little bit ago.

I'm still waiting here in GFK (and to a lesser degree, DFW) to see what happens when the CR9s and E70s come into service.