Not sure what you mean "something might happen with MDW" - as CO is shutting down. CO had scaled back MDW with RJ's and Q400s and now closing. Even ORD is reduced with the RJ's to CLE, and 735s to EWR.

Now IAD is another issue. CO has scaled back IAD operations so much - I am not sure if it is worth CO flying there. I believe it is only RJ's now, and RJ's are not cost effective with 50 seats. I even see a decline in the number of passengers out of DCA on CO, with many empty seats and some DCA flights shifting to RJs. CO has so much focused on its orginating hub traffic, I think they are losing passengers elsewhere.

Maybe CO will get out of its small markets - many of those served only with RJs. But that was the rationale for getting the RJ's - to serve small markets.