Some of these violations are common and ubiquitous. It's been well-known for decades that the UK train fares are not a metric, for a time even failing all three properties:<p>* Splitting tickets at an intermediate station sometimes reduced the total fare, so p(A,B)+p(B,C)<p(A,C);<p>* Reverse journeys are not always the same price, so p(A,B)!=p(B,A); and<p>* For a time it was necessary to purchase a platform ticket to enter the station proper, so p(A,A)!=0.<p>Even now I save thousands of pounds a year by finding optimal split ticket journeys, some of which take (partial) advantage of advance fare discounts.<p>So I'm not surprised, and no longer think of common sense as something to be expected from fare structures.
"Common sense" tells us that air ticket pricing will be heavily optimized to maximize airline yield and that no effort is made to conform to any naive buyer conveniences or expectations. Although the data is interesting, the premise of this paper is a little weird.
The article looks at common sense from the passenger point of view, but in fact if you look at it from an airline point of view you can sometimes see a very different picture.<p>For example, take the following 2 principles, each of which make sense individually:<p>1. A non-stop product from A to B is a superior to a one-stop product from A to B. Therefore, A to B non-stop is priced higher.<p>2. If only one airline has a non-stop product from A to B, they will price it higher than if multiple airlines have a non-stop product from A to B.<p>Let's see how this can play out in practice:<p>If many airlines can offer a one-stop product from A->B, your airline will offer it cheaply to compete. It may just so happen, as an implementation detail, that your product happens to connect at C since that's your hub.<p>Now, if you look at the A->C market, you may have the only non-stop product, and thus you price it high.<p>Result, your price for an itinerary (remember the actual itinerary is an implementation detail of the A->B one-stop product you purchased) from A->C->B is priced much lower than the person sitting next to you that is travelling from A->C only, even though the direct fuel cost to the airline of A->C->B is clearly higher than A->C only.
I'm curious how this was funded. If the authors had asked most anyone involved in Airline reservation management they would have told them this plain and simple as it is no secret. Yield management and airline network dynamics are just some of the drivers for these "common sense violations".<p>Also just to correct another comment on how often fares change. For international flights airlines can publish new fares to ATPCO up to 10 times per day however with newer pricing strategies/technologies such as bid-price the fares can change to meet the demand curve in near realtime.<p>Airline pricing and revenue management is a very complex and interesting topic that has always pushed the envelope of technology and business management. There is a reason why google purchased ITA. I was really excited to see a paper on the topic post on HN but in the end this study has very little substance to add to the many bodies of work out there.
Nice, now how can I use it to get a better fare?<p>I see that I should:
* search for the round trip even if I go in just one direction
* try to buy each connection separately if I have time to spare (maybe using multicity).<p>Any more tips? Is there a nice system that would automate it for me?