> This is a result of a strange pricing algorithm mistakes, right? Surely this doesn't maximize profit
They tend to tier things so business travelers will pay more, so there may be fare rules that increase the cost dramatically the closer you get to departure date, or charge more if you do not stay a certain number of days (I've heard one week as well as requiring a 'Saturday stayover')
Of course business travelers are the ones most likely to research and plan out how to get around these, so they might book overlapping tickets pointing opposite directions and interleave them. Airlines get upset about this, but they also know that if they try to crack down that these travelers will just take their (substantial) business elsewhere.
> This is a result of a strange pricing algorithm mistakes, right? Surely this doesn't maximize profit.
The Saturday night stay rule is alive and well in certain markets. Business travellers like to be safely back home before the weekend, and their [employer's] pockets are deeper than leisure travellers.
The average leisure traveler typically isn’t taking a two-day international trip. Airlines see an opportunity to extract more profit from business travelers who may not know their return date.
A significant example is Lufthansa (and co) — multiple thousands of dollars to book a one way to Europe, under 800 for round trip.
That’s called back-to-back ticketing and the airlines really don’t like it. You can easily get your frequent flier account closed for doing that, if not sued for the price difference.
That site is named after the practice, not the other way around, and the article is far more informative on how it all works (as well as the steps airlines take to combat it).