Little correction there 700. You see, Republic and Usairways did to J4J when republic bought the 170's. You are correct though that j4j was a pilot thing.
I think what someone was alluding to, that in the lift agreement between republic and usairways, it may state that republic will be handled by Mainline, though not sure about that because the 170's started in C con in CLT, then shifted to Express for a year or so, then back to C con.......Think it had to do more with parking on the gates when the E terminal was expanded and such. They could shove more in there with 900's parking on E then with the 170's...