The last time I booked a hotel on Orbitz, the site said the transaction could not be completed yet days later booked multiple rooms until my card maxed out. In the process of trying to correct this, using the company name making the charges, I discovered that the reservation system Orbitz uses is the same as for Priceline, Travelocity, and other major travel sites. WTF?

1) Southwest's fares did indeed appear on Travelocity at one point.

2) In some cases, it is indeed the airlines who don't want to appear on OTA (online travel agency) and aggregator sites. This is the case with Southwest for sure. Even Southwest sometimes undersells themselves with their Ding! fares, which don't appear on their own booking engine! (Speaking of off-market fares, check out American's 25% off Caribbean fares, yours if you use the secret promo code).

3) However, it is *totally* true that some airlines are included by some sites in the spirit of fairness, and others don't include these airlines. Sidestep lists airlines that Orbitz does not; these airlines don't pay either site to be listed. An airline will remove their fares from a site if there's a commission or payment dispute with the OTA. You won't even notice their fares are gone.

4) The recommendation to use farecast and farecompare is truly ironic, since those sites don't forecast or compare fares on Southwest, Allegiant, SkyBus, etc, and that was my whole point in writing the original article: never ceases to amaze.

5)The listing or de-listing of airlines on certain sites has nothing to do with their status as charters or whatever, and everything to do with profit. Southwest does not want to pay Expedia et al. to sell seats on its planes when it can easily to the job itself for less money. They don't want their fares to be compared to other airlines; they want the flying public to assume that SWA has the best fares every time, and often, they do.

6) I think the bottom line is that you have a better chance of seeing fares on all airlines in one place if you use a site like Sidestep vs. Orbitz, at least for most domestic fares; and you just have to remember to look at SkyBus, Allegiant, USA3000, Southwest, and Virgin America sites if you're flying routes covered by these airlines.

That may appear to be so to the layman, however; Its not quite true. All of those airlines, with the exception of Southwest are commonly known as Supplemental 121 airlines. Part 121 in the Federal Aviation Regulations is scheduled air service. In order to get a certificate, one must follow all the regulations. Airlines like Skybus, Alliegant, USA3000, and who could forget Hooters, etc actually operate more like a charter flight, which is Part 135 This is why you will not see them listed on travel sites. Its typically part of the business plan for these airlines. For instance, if Delta, a part 121 airline schedules a flight and only one person shows up, they are legally obligated to fly that flight. A 135 operation would not have to fly the plane, and could simply put that one person on a competing or partner airline. cc Ben

Off-topic, but the first site my family ever used for booking airline tickets was www.itn.net - and woah, look, no Southwest.

This is totally true. Southwest just refuses to be listed on those sites period, and their fares are dirt cheap usually so I always check their site. Also I have found, in my comparison shopping, that flights booked directly at the airline site ARE NOT more expensive than flights booked on the third party sites. I always book directly with the airline. Saves on fees and saves a lot of hassle if there is a delay or cancellation.