This is a complete list of all airport/airfield/aerodrome IDs for use when flying the Su-25T. It has data for the following maps: Caucausus, Nevada/NTTR, Persian Gulf, and Syria. This is only a plain text file, feel free to do whatever you want with it.
These IDs were all found manually by spawning an Su-25T at every airport on the map, then checking the RTN or LNDG nav mode to show the airport ID in the HUD. I tried to make sure it was accurate, but no guarantees. I don't have the Normandy or Channel maps so if anyone would like to make a list of IDs and airport names for those and send them to me, I'll add them to this file.
See also this forum post: https://forums.eagle.ru/topic/261935-su-25t-airport-ids/
(I believe these IDs are also used by the Flaming Cliffs 3 planes, but they don't seem to show what waypoint number (or airfield ID) you have selected, so these IDs may not be much use for FC3.)
Additional keywords: navigation, airport, airfield, aerodrome, su-25