It is fact that the CRJ burns less fuel than the 170.

It is fact that RAH has around an 21% lower operating cost per seat mile than SKYW.

Fuel is an issue but it isn't the only one. On a 2.5hr leg where are they saving more money? Using rough numbers for quick math lets say there is a 1000mile trip.

RAH would be break even at about $5320.
SKYW would break even at about $6790.

As you can see there is a $1470 difference. So JetJock lets take your 200lbs per hour of fuel saved and say this trip. That's 500lbs of fuel. Using 6.767 as our base weight for fuel that's 73.88 gal that CRJ saved the company. Lets double that amount and say you saved 1000lbs of fuel. You saved them 147.78gal of gas. A considerable amount yes, but do you think it still offsets the $1470 difference? Jet fuel would have to be around $10.00 a gal to make the difference. So who's actually cheaper? These are just break even points and obviously both companies charge more per ASM. However this does give RAH a HUGE advantage even if the 170/175 burns more per hr. These are based on 70 seats.