Difficulty level: Hard. But you can solve this without detailed knowledge of the airline industry.
Last night, I was trying to a book ticket LAX-SFO on July 14. I’m going to YxYY in Palm Springs and need a way to get back home. Around 9:55, I did a Kayak search, as I often do, to start the process. I saw that Virgin America had a fare of $91. I went to the Virgin America site and saw the $91 fare. After I selected the seat, I got a message that my seat was taken. I re-ran the search and saw that the lowest fare on July 14 was now $140. I checked on Priceline. Same thing.
I looked at the clock. It was now 10:03. I knew exactly what to do: I went to Expedia and booked the ticket for $91. In addition to inconveniencing me, Virgin America lost whatever they have to pay to Expedia.
Why was I able to book the ticket for $91?
Note that this is not a one-time fluke where there is a fare mistake. I have taken advantage of those in the past; I once flew roundtrip business class to London for less than $91.
If you’re in the travel industry, instead of commenting, please send your answer to firstname.lastname@example.org.
The solution is here.