Airport Codes (APCodes) 1.4a
This provides a list of every public airport in the United States and the most popular 275 international airports with their elevation, city name and other details.
This has a database that is updated every 56 days. It's available in multiple languages and offers full search capability. You can locate airports by A/FD (Airport and Facilities Directory) region, city/town name, elevation or ICAO identifier (non-US airports only).
Requires PalmOS 3.5 or above.