For most commercial carriers the AirlineFlightSchedules query could be used to get more precise information about the flight with only a flight number and approximate times known so long as the anticipated departure time is between the supplied startDate and endDate.
FlightXML requests, like this one, will normally work for up to two weeks of recent history unless otherwise stated.
Using the ident@departuretime found in schedules as the faFlightID in GetHistoricalTrack will allow you to get the results still. There’s no implied limit to how far back this method can search. However, there is also no garuntee a flight in a historical schedule actually occurred. A “flight not found” error may occur in the case of a cancelled flight. This could be checked by providing the same ident@departuretime to FlightInfoEx so long as the flight is less than two weeks old.
Indeed I see some inconsistency between AirlineFlightSchedules and GetHistoricalTrack. How I can use GetHistoricalTrack for searching old flights (for e.g. up to 6 months old) if I’m not able to retrieve the exact departuretime from the other “search family” APIs for those old flights?
In our case not always the airlines send us the exact time of departure, many times we have only flight number and date of departure, not the time.
Would be possible to extend the AirlineFlightSchedules to look back for the same period of time of the GetHistoricalTrack?