After posting about the difficulties in reserving a mixed US Airways-United itinerary on either airline’s website last week, I contacted the two airlines about their codesharing policies, looking for some clarification. I’m pleased to report that US Airways has replied with a detailed response.

I asked Valerie Wunder, Associate Manager of Media Relations, to clarify why United-operated flights that had a US-codeshare weren’t coming up on usairways.com. (I asked similar questions of United Airlines, but have not yet received a reply.) She responded with a great, detailed e-mail, the bulk of which is quoted below the jump.

Four things stand out for me:

1) My observation that codeshared flights were restricted from sale (and not simply sold out) is largely validated, though my suspicions for the cause of the restriction are in dispute. Two reasons for the failure to list all codeshares are cited: “System migration issues” and “minimum connect timetable issues.” The former reason makes some sense, considering the integration of America West with US Airways systems has been incremental and problematic. Why should codeshare sales be any different?

But the minimum connect times? Over an hour’s connect time at CLT shouldn’t be an issue, so either the computers are being overly aggressive in blocking out partner flights with “short” connects, or this is a red herring.

2) United isn’t codesharing on the US Airways flights that are technically still operated by America West. United also isn’t codesharing US Airways Express flights when the plane has a capacity greater than 69 people. In both cases, “commercial reasons” are cited. Hmm…

3) US can’t sell UA nonstops if they operate the same exact nonstop route. ORD-CLT and ORD-DCA might be such routes. But they can sell these flights if they’re part of a connection.

4) More codeshares might be hard to come by, because they’re running out of numbers to use.

The bottom line from the airline’s corporate HQ is that US Airways’ website and reservation center still have a few more kinks to iron out of their system. They admit as much. And they admit that other booking sites may come up with more options (which is somewhat like throwing in the towel…)

Read the complete official explanation after the jump…

Thank you for inquiring regarding the US – UA codeshare program. Reports of the demise of the UA-US codeshare program are greatly exaggerated!

First, regarding UA sales of US-operated flights:

- www.united.com sells UA* flights operated by US with almost no bias against the US-operated flights when searching by schedule, perhaps some bias for UA operations when searching by price;

- UA* code not yet on US flights operated by America West, for commercial reasons; we expect this to change later this year;

- UA* code not placed on US flights operated by affiliate partners using aircraft with more than 69 seats, due to commercial issues; use of these aircraft by US partners is expanding, which has had a minor diminishing effect on the program.

Second, regarding US sales of UA-operated flights:

- www.usairways.com does not display UA flights as it once did; your observations are fairly accurate; new limitations are due to system migration issues, and should be addressed yet this summer with increased visibility of US* (UA-operated) flights;

- US* codeshare sales are not restricted at US reservations, by policy or schedule display. Generally US* nonstops and connections, operated by UA, are displayed in our reservations system and will be sold by our reservations agents. In researching your experience, we found many connections – though indeed not to the CLTORD flight you listed; this appears to be an anomaly through our Minimum Connect Time table, which we are attempting to address;

- We temporarily inhibited some US* code in four markets: PHX, LAS, BOS, and DCA. This again is related to Minimum Connect Time table issues, which should be resolved in the coming months to let those markets come back.

Third, other general comments:

- U.S. government restrictions will always prevent sale of US/UA codeshares in competing local market nonstops; for example, UA* on a US operation CLTORD can only be sold in conjunction with other UA flights at ORD, or other UA* flights at CLT;

- A Dividend Mile member does not need to fly on a US* flight operated by UA to gain DM mileage — they can fly on a UA flight operated under its UA flight number;

- The programs include approximately 2000 UA flight numbers on US, and 2000 US flight numbers on UA — by far the largest bi-lateral codeshare in the business; growth beyond this is mostly restricted by a lack of flight numbers;

- US currently includes other carriers’ flights on www.usairways.com only as US* codeshare flights; we are looking at changing this in future development, but it will be done selectively, as the pricing of “interline” itineraries is more complex;

- Tens of thousands of passengers find a way to book our UA codeshare flights each day, either through travel agencies, websites, or reservations offices; we work continually to improve access to the program.