In Memoriam, FlyerTalk Evangelist
Join Date: Jul 2002
Location: Durham, NC (RDU/GSO/CLT)
Programs: AA EXP/MM, DL GM, UA Platinum, HH DIA, Hyatt Explorist, IHG Platinum, Marriott Titanium, Hertz PC
Posts: 33,857
I've had the opposite experience of the OP. Ever since United started ordering more 737-800s/900s and picking up used A-319s they've been putting mainline onto routes that didn't used to have it. RDU-IAD/EWR/ORD for example has a much better shot at mainline now than it did five or six years ago. The same can be said for EWR-IAD which was all Express until recently.
Delta is similar ever since they bought so many 717-200s. Even tertiary cities get mainline now (AVL/FAY/GSO-ATL etc.).