FAQ
What airport codes are these?
The airport codes are ultimately derived from the codes established by ICAO.Wikipedia has a great overview.
What about the aircraft?
Similarly, aircraft type designators are contained in a standardized ICAO database. ICAO has a public list on its web site. There is also a good overview (with some examples) on Wikipedia.
NB: For practical purposes, only designators of exactly 4 characters are included in Flyable.
Spoilers?
Share your game with your friends, but make sure you don't let the answer slip!