Right; my point was just that they know this. As for demanding a loyalty premium when they're not offering a nonstop -- I bet they have a large number of corporate contracts in Houston. Those contracts tend to be written as percent-off deals based upon the fare class, so they may be keeping their retail prices high in order to keep their contract prices competitive.

That said, you may just be running into inventory issues on the dates that you're looking, or you're running into a business traveler surcharge that other airlines might not be charging. I did a sample search for economy IAH-CDG 10/16 - 10/25, and Turkish was very cheap (but way out of the way) and AF / DL / AA / UA were all the same price at about $1480. If I do an earlier return --- 10/16 - 10/19, Singapore / flybe becomes the cheapest at $1470, then Turkish and AM at $2000, and then Lufthansa and United at about $3900; DL/AF is several hundred dollars more at $4600. So it's really hard to do this kind of comparison in a vacuum.

I can assure you, though, that if they thought they could do the same thing in other cities, they would. In some cases, they do -- UA is accused of "fortress hub" pricing at SFO and EWR, just like AA at CLT and DFW and DL at DTW and ATL.

The airline business is extremely difficult to break into. If all of the existing airlines were to raise fares in concert, they might get away with it. If UA were unilaterally to double fares across the board -- well, I don't think Scott Kirby is that stupid.