Everyone brings up some good points about RJ's vs 717, 737, E190 etc. I really don't think there is a clear cut answer to which is better or more profitable. It all depends on matching the appropriate a/c to the most suitable market and vise versa. Frequency has a lot to do with it also. 8 flights a day in a 50 seat vs 3 flights a day in a 717, or 8 flights a day in a 717 vs 2 flights a day in a 747, more flights provide for more flexibility but ticket prices might be a little higher for the 50 seater as compared to a 717 in order to be profitable.
By the way Independence air is about to test this argument of 50 seaters (CRJ's) vs 132 seaters (A319's) with their LCC plan. It will be extremely interesting to see how they utilize the CRJ's in a LCC type of operation. Some say it will fail, others say it will work because they will match the small markets with the CRJ and the bigger ones with the 319/320.
By the way Independence air is about to test this argument of 50 seaters (CRJ's) vs 132 seaters (A319's) with their LCC plan. It will be extremely interesting to see how they utilize the CRJ's in a LCC type of operation. Some say it will fail, others say it will work because they will match the small markets with the CRJ and the bigger ones with the 319/320.