[melvinmt]

You should first start reading these great slides from Carl de Macken (ITA Software co-founder, the thing that now powers Google Flights) http://www.demarcken.org/carl/papers/ITA-software-travel-com...

…and then decide if you still want to pursue this.

[dmbaggett]

Short answer: you don't!

[jaza]

Great read! Incredibly thorough modelling of all components of the flight ticketing problem space, and of the computational complexities involved. Sets a high bar as an example of how to thoroughly model any search-related problem.