NWA will be parking 30 of the remaining DC9-30s this year, and supposedly keep 68 DC9-40/50s. Would they just park them all with no replacement and take them off their trunk routes (probably GRR, Minot, Fargo, Winnepeg, etc) and give them to RJs, when they probably fill those flights with well over 100 seats each? Probably not. They would slowly park those 68 planes when they can find adequate replacements (like MD90s---Saudia just put 28 up for sale--and many are available in China and Japan). Compass will have 38 total E170s by the end of this year, mostly making up for those DC9-30s. The Mesaba CR9s are covering for the Avros that left for Cityjet in Paris. The 68 larger DC9s will probably be replaced by 737NGs that may be coming off of a new production line added by Boeing in the near future. (article in WSJ stated they were thinking about adding a new production line soon) Highly doubt they will just park every DC9 as soon as we merge (if we do at all).
Bye Bye--General Lee