ITA Software Matrix Tool - This tool allows you to search for fares in different sales cities so that you can accurately plan purchases in any city around the world. Additionally it has an undocumented feature that allows you to specify specific fare buckets. If you want to, for instance, search for A bucket availability on the HKG-JFK route on Cathay Pacific you would enter the search as From: HKG:: cx+ / f bc=a and To: JFK:: cx+ / f bc=a. You can substitute the "cx" with the proper airline code for the airline you wish to check, and substitute the "bc=a" with "bc=X" where X is the fare bucket you wish to check. If you wish to check multiple booking-codes and not place any restriction on the airline format the request as JFK::/ f bc=x|bc=y|bc=z to check the x, y, and z buckets. Another undocumented feature is the ability to request multiple segments on specific carriers (useful for mileage runs). If you want to travel from Los Angeles to New York and take 4 American Airlines segments, you would enter the departure city as LAX::AA AA AA AA and the destination city as JFK::AA AA AA AA. This will search for a 4 segment connection in each direction on AA. You can also force connections in specific cities. So, for instance, if you wanted to connect in STL from LAX to JFK on American Airlines you would enter the departure city as LAX::AA STL AA and the destination city as JFK::AA STL AA There is a full description of various commands the ITA system allows you to use at their Route Language page.