I am trying to book a flight from A => C on flightnetwork.com. I find a flight at a good price but with a 20 hour layover in B. B is a nice city so I thought since my schedule is flexible I would book the first leg of the flight separately, stay a few days then travel to C. However on the search engine, flight A => B only appears when searching for the A => C with the return ticket. If I search for A => B it does not appear on the result list at all.
Can anyone explain how this works?
Thanks
Basically, the airline for some reason considers it more advantageous to sell the A => B seat as part of an A => C journey than to sell it alone, probably because an A => C ticket brings in more revenue than an A => B one.
A => C could also have more demand than A => B, so the airline doesn't want to sell an A => B ticket and miss an A => C customer later. Or maybe A => B and A => C have similarly strong demand, but B => C has much less, and the airline prioritises A => C over A => B because it allows them to fill their B => C flights as well.
Ultimately, there is no way to know for sure, but be assured that the airline knows what they are doing. They pay people a lot of money to figure those things out.
The scenario you describe is not uncommon and there are a couple of legal/political and marketing-related reasons why it would be the case.
Cabotage/Freedoms of the Air
The airline may lack the rights to carry passengers from A-B, though they can carry them A-B-C. For example, if the segment is domestic and the airline is foreign, the airline must have rights of cabotage. Most countries prohibit foreign carriers (whether in the air, on land, or at sea) from competing with domestic carriers, the only exceptions lying within certain economic blocs such as the EU.
For example, Qantas QF108 currently flies between New York-JFK and Sydney via Los Angeles. Qantas is an Australian airline. Australia and the United States do not have a treaty that allows cabotage, so Qantas is forbidden under U.S. law from carrying passengers between points within the United States. Thus, you can book a flight on QF108 JFK-LAX-SYD, or LAX-SYD, but not JFK-LAX.
Price Discrimination
As with so much in airline pricing, there are mysterious algorithms based on historical travel patterns and revenue projections behind every fare quote. It is entirely possible, for example, that US Airways might be willing to willing to sell you DCA-PHL-MAD ticket but not DCA-PHL, perhaps trying to keep those seats open for passengers with higher revenue onward connections. Certainly, flights such DCA-PHL are priced considerably higher than one might expect based on distance or demand, in part for this reason.
There are a few more remote possibilities, like technical stops being represented as intermediate destinations, or a segment of a direct flight being unavailable for separate purchase, but I believe the above two should over most cases.
