Whats up with all the airlines starting to use "regional jets" for long hauls?

Cost. They cost less to buy and less to run, so they are much cheaper to fly. Moreover, the crew costs less. Most of them are working for a "partner" airline, and their pay is MUCH less than a major airline crew would get paid for the same flight, plus there is usually only one FA and on and on. When I feel annoyed by the prospect of a long flight on a small jet, I just tell myself it's my Gulfstream V, the stripped down model!

The 50-seat RJ fad has been over for a while. Indepedence has shut down with its planes parked in the desert, and Continental is soon going to lose 69 of its ERJ fleet - they most likely will be flying in Europe instead.

Canadair and Embraer has basically stopped their production line for them.

The current trend is towards larger RJs. 80-100 seater that's not much different than the old DC-9s. And shorter routes will see more turboprops, like the new-design 70-seat 400Q.

At DFW and cleveland the fad must have just started, as 75% of the fleets of American and Continental are RJ. Anyway that was the way the terminals and runways appeared this weekend. That route was 3 hours on this size plane. What's next coast to coast flights on RJ?

At CLE, yes you'll mostly see CO's ERJs. It's basically a regional jet hub, so is DL's Comair hub at CVG. These cities really cannot support a full hub of mainline jets if you want decent frequencies.

DFW is AA's headquarters. You'll see a lot of their ERJs, but a good portion of their flight there are mainline.

But anyways, it has been like this for at least 4-5 years. Nothing new.

As for long routes, the longest 50-seat RJ route is probably CO's Houston to Boise, at ~1,480 miles. UA also uses a lot of their 70-seat CRJ-700 for destinations in the Rockies at 1,300-1,400 miles.

Fact is, props don't have this range, so the choices are really RJs with higher frequency, mainline jets with few frequencies, or no service.