Based upon federal 2Q10 air transportation data (select table 6). Out to about 1,200 miles. Close enough, in other words, for 50 to 86 seat regional jets to fly to:

Destination Code Miles Value Pax/Day Avg Fare
Omaha, NE OMA 913 $16,801 63.0 $266.82
Des Moines, IA DSM 815 $15,313 52.5 $291.52
Oklahoma City, OK OKC 940 $13,382 42.4 $315.47
Burlington, VT BTV 761 $12,347 78.7 $156.93
Grand Rapids, MI GRR 583 $12,166 57.0 $213.32
Tulsa, OK TUL 842 $9,872 30.2 $326.66
Wichita, KS ICT 933 $8,664 48.7 $177.98
Madison, WI MSN 708 $6,769 39.8 $170.15
Cedar Rapids, IA CID 742 $6,729 32.7 $205.49
Moline, IL MLI 674 $5,988 30.5 $196.00
South Bend, IN SBN 534 $5,752 26.9 $213.66
Flint, MI FNT 555 $4,915 26.8 $183.30
Green Bay, WI GRB 745 $4,610 20.8 $221.97
Ft. Wayne, IN FWA 460 $4,551 25.8 $176.22

Value is what people spent on average per day flying between Charlotte and the city in question. It’s simple the next two columns multiplied together — the number of people flying between the cities and the average one-way air fare. Connections going through CLT are not included. And yes, there are another 17 places that do at least 10 passengers a day.

The pattern here is rather obvious: With one exception, the biggest markets US Airways doesn’t serve are the second-tier destinations from Oklahoma around to Indiana. The average fares to some of these places — think OMA, DSM, OKC and TUL — is actually higher than on flights to the West Coast from Charlotte (LAX average fare: $252.83, SFO $289.76).

As we’ve previously mentioned, US Airways has focused over the past three years on adding service from its Charlotte hub to smaller markets from Florida to Texas. They’ve done pretty much all they can do there. For comparison, here are the numbers of Melbourne and Baton Rouge, which US Airways added in 2010:

Destination Code Miles Value Pax/Day Avg Fare
Baton Rouge, LA BTR 675 $5,136 23.4 $219.42
Melbourne, FL MLB 490 $4,527 25.8 $175.32

So if those two can work, then some of the Midwest markets should definitely be viable as well. US Airways even already flies to Omaha and Des Moines from Phoenix. Yet so far, the airline has been unwilling to expand into those two cities or other secondary-tier Midwest markets from CLT.

Maybe that will change by next Christmas. Maybe.