OpenFlights Airline Schedule Data Survey
OpenFlights is considering launching a new service to supply airline schedule (timetable) data. The data would contain the following fields per row:
Source airport, destination airport, start date, end date, days of operation (days of week), departure time, arrival time, flight number, aircraft type, flight duration
LCG,MAD,-,2013-07-19,1 2 3 4 5 6,13:25,14:45,IB513,320,01:20
LCG,MAD,2013-07-22,-,1 2 3 4 5,13:25,14:45,IB513,320,01:20
(This is an indicative sample, not the final format)
Due to the effort involved, up-to-date schedules would be a paid service. However, historical data would be made available for free.