Apparently .aero originally reserved all three letter domains for IATA codes, but only a couple hundred airports took them up on it https://www.information.aero/airports_codes_released
For a sense of scale on 'only 227 registered one', there are currently 9161 IATA airport codes
TIL there's an observed pattern of Russia's state leaders alternating between bald(ing) and hairy https://en.wikipedia.org/wiki/Bald%E2%80%93hairy