Where did the airport code databases come from?
The IATA and ICAO databases were initially derived from a database which once lived at the Johnson Space Center, subsequently augmented with material from a variety of sources. Most ICAO data now comes from NGA’s DAFIF® product (see Credits and Copyrights), which offered excellent data quality. Unfortunately, NGA ceased distributing DAFIF® except within the military effective 1 October 2006. The airport database uses the final public DAFIF® data (cycle 0610, effective 28 September 2006 to 25 October 2006), IATA charges a large and recurring price for their data, so airport locations for non-US IATA codes (and scattered ICAO codes) continue to be derived from a patchwork of sources. While most major airports are now included, given the unknown ancestry of the data, the accuracy of the data is often suspect. Special thanks to Thomas Jger, Iikka Merilinen, Yann Gascard, and Nils Rennenberg for their assistance in cleaning up this mess as much as possible. Authoritative data is used for US
