Also, they could have sold that ticket to someone else, and they wouldn't need to wait for the last second (or beyond) to close the gate while paging the traveler that never arrives throughout the whole terminal.

It is definitely NOT cheating. This argument also assumes that flying from A->B somehow has higher value than flying from A->B->C which is saying a beef patty is more valuable than a burger that has has the same beef patty in it. As far as I know the airline industry is the only place where "A" is more expensive than "A+B" is considered normal pricing practice.

@Hilmar It might well be argued (I'm a recovering attorney) that intentionally violating the Terms & Conditions of the ticket purchase — to which the purchaser agreed — is indeed "cheating."

@Hilmar your analogy is incorrect. You're not buying a product, you're buying a service, and the service is getting you from point A to point B. That is priced accordingly. You then basically stop the bus mid-way and exit at point C that the bus (or the airplane) happens to pass through and get out, but the service you got (getting you from point A to point C) is actually much more expensive for <reasons>. You knew that, and yet you intentionally lied to the service provider to get the cheaper pricing. That is most definitely cheating.

@Hilmar a direct flight has more value than an indirect flight for the same endpoints, that’s a fact. Many of the examples here are incorrect: flights A-B-C where A and B are large airports and C is a minor airport are usually not cheaper than A-C, simply because there are no A-C flights, and not cheaper than A-B either. But if C is another major airport with direct flights A-C, it’s nearly always true: the only reason people pick A-B-C over A-C is because it’s cheaper: who wants the trip to be longer, more tiring, more risky (missed connections…)?

In a competitive market, shouldn't the price be set by the supply side cost, not the "market value" to the customer? The supply side cost of two flights is obviously higher than the cost of just one flight, so it seems like there isn't enough competition in market. I'm guessing that's the cause of the confusion.

@craq The flights are operating no matter what (at least until they get so unpopular that the airline cancels them or goes broke), and the marginal cost of adding an additional passenger is quite small (yes, the additional weight burns a bit more fuel, and don't forget a couple cents for your bag of peanuts). The airline is trying to maximize the profit they get from the flights they have already scheduled. If the airline has seats on a scheduled flight they can't sell at a higher price, they might as well sell them for cheap because that still beats $0 if the seat flies empty

No, first because they are trying to cheat you.

@jcaron I don't think anyone is comparing A-B-C flights with A-C flights. As you say, cutting out an intermediate destination has actual value and is legitimate to charge for. By contrast, Hilmar compares an A-B-C flight with an A-B flight, where there is no difference whatsoever for the passenger travelling to B. Charging more for a service which transparently requires less work due to an arrangement you have with a third party is profoundly unintuitive for a customer who has no visibility or control over those agreements, and some commenters seem to consider it unethical.

@preferred_anon I mean an A-B-C flight to "Bumblebutt" is unlikely to be cheaper than an A-B flight, because there are no A-C flights to compete against. It is actually likely to be quite expensive. A LAX-ORD flight can be as cheap as $100. A LAX-ORD-CMI flight is 5 times as expensive, because there are no LAX-CMI flights, and AA are the only ones serving CMI.

@jcaron Well, then I don't think I understand your comment well at all. The premise of the question is that one is skipping the B-C leg to save money. If missing the flight does not save money, then any rational person would take the cheaper flight. A case where A-B-C is cheaper than A-B may be rare (you'd hope so!), but it clearly exists, or Skiplagged would never have existed in the first place.

"Cheating" is an extremely morally loaded word that's probably not appropriate here

@preferred_anon My point is that the examples given in this answer and others ("BumbleButt", Duluth) are not representative. Those which are representative usually involve a larger destination. It's not because the destination is less desirable (quite the contrary), it's because there are direct flights or more competition that the prices go down. Small regional airports have little competition and few direct flights.

Do you have evidence or can cite a source showing that "Bumblebutt" communities in the US are subsidizing flights to themselves? (aside from, for example, by making use of their airports available below cost)

Since @Hilmar brings up burger pricing, I'm relatively sure there are places with menus where a 'cheeseburger without cheese' can be cheaper than a 'beefburger'!

@ScottishTapWater Would stealing be a better term? If Bumblebutt pays for part of your airfare so you fly to Bumblebutt, and you don't follow up on your end of the agreement, you have taken their money.

@Hilmar "cheating" deleted. But you do realize "it's not cheating" is indeterminative :)

@ScottishTapWater "cheating" removed.

@rtaft as other comments have remarked, that's generally not what's going on. Bumblebutt isn't paying for part of the airfare, the airline itself is doing it, and only because there are competing flights that the customer would have chosen otherwise. If we're going to use loaded words, I'd suggest this: the airline bribed the customer into not-flying-with-their-competitor. Is it stealing to take a bribe and not follow up on the associated demands? Perhaps. But the unethical bit isn't the stealing, it's the dealing with someone who hands out bribes in the first place.

@ThePhoton Many regional airports provide subsidies to airlines, either relatively directly (e.g. the airport's county providing subsidies or guaranteeing a minimum level of income) or via larger programs, like en.wikipedia.org/wiki/Essential_Air_Service. (I don't know if those subsidies are enough to make the A-B-C flight cheaper than A-B, but the subsidies do exist.)