I am so sick and tired of people saying that since AAI,WN and JBLU don't have RJ's, then RJ's must not be feasible. Now let me ask you, how many small/midsized markets do AAI,WN and JBLU serve? Every market JBLU serves has at least 1 million people (except BTV which was largely political). WN rarely touches a market under 500,000 (save for a few legacy cities in TX). AAI has ventured into a few smaller markets but now requires massive subsidies in order to enter smaller markets. So if we all follow the WN,JBLU and AAI, there's going to be about 250 cities with no chance of air service. According to the business models of those carriers, smaller markets can go to h*ll.
RJ's aren't perfect and they won't save any airline. But they can make a difference. Yes, CAL and DAL have lots of RJs and are still losing money. They also lost money during the last recession when there wasn't an RJ in sight. However, CAL, NWAC and DAL are the closest to being profitable again (w/o filing for BK, asking for massive concessions or ditching half the fleet).
RJ's are part of that success. RJ's allow DAL for example to keep and expand the DFW hub. There's no way the DFW hub would still be alive w/o RJ's. Yes, DL had to slash out a lot of mainline, but what should DL do? Fly around MD88's with 50 people forever or fly an RJ with 50 people around and make money. RJ's are the only way to keep some of the smaller hubs alive....SLC, DL's DFW, CLE, CVG, PIT, MEM, HP's CMH,etc. This is why RJ's are so important for U....two of U's three hubs are relatively small in O+D terms and w/o RJ's, these hubs cannot effectively compete in the market anymore.