DAL-ATL seems like a good fit for the Boeing 717. I would imagine CR7/CR9 for the other cities. In the end I just see this as DL trying to squeeze the competition for as much as they can and this new service being discontinued fairly quickly. Look at Houston Hobby, DL only has service to ATL and that is all I think they will ultimately have out of DAL.

Outside of ATL Delta really doesn't have much service to DFW. Looking at the schedule today MSP is all on RJ's and of the six DTW flights half are operated by small guage mainline planes and the other three are RJ's. CVG is operated by three large RJ's. LGA and JFK are also operated by large RJ's. MEM still has two CRJ-200's but let's be realistic; those flights will be gone very soon.