FlightXML

Using the FlightXML API, programs can query the FlightAware live
flight information and historical datasets. Queries for in-flight
aircraft return a set of matching aircraft based on a combination of
location, flight or tail number, origin and/or destination airport,
aircraft type, and/or a low-to-high range of altitude and/or ground
speed, among others. For each matching aircraft, data returned
includes the flight or tail number, the aircraft type, origin and
destination, time the last position was received, and the longitude,
latitude, groundspeed, and altitude of that position. Matching
flights' flight tracks can be requested as well.

For airports, FlightXML queries can return a list of scheduled
flights, flights that have departed, flights that are enroute to the
airport, and flights that have arrived at the airport.


http://flightaware.com/commercial/flightxml/