Where can I find a free list of ICAO and IATA airport identifiers? Is there an open source or free comprehensive (or close to it) list of ICAO to IATA airport identifiers? The official list from ICAO costs hundreds of dollars. I suppose such a list could be scraped from Wikipedia.
It depends on whether it should be reliable enough to be used operationally. If yes, I don’t know one and would to the best of my knowledge advise spending some sort of money. If no, maybe openflights.org could help?