| 1 | RKH | Royal Khymer Airlines | IATA: FE, Callsign: Khymer Air, Designator FE recalled by IATA | K | AVCODES |
| 2 | RKH | Royal Khmer Airlines | IATA: RK, Callsign: Khmer Air, Designator RK reinstated by IATA. Designator FE recalled by IATA | K | AVCODES |
| 3 | RKH | Royal Khmer Airlines | IATA: RK | | ICAO1 |
| 4 | RKH | Regionalverkehr Kurhessen GmbH | | D | TRAFFIC |
| 5 | RKHA | ROCK HAULERS INC | | | SCAC3 |
| 6 | RKHA | ROCKET DELIVERY INC | | | SCAC4 |
| 7 | RKHD | RKH INDUSTRIES INC | | | SCAC4 |
| 8 | RKHI | RICH TRUCKING INC | | | SCAC4 |
| 9 | RKHJ | ROCKHILL, H J INC | | | SCAC3 |
| 10 | RKHU | RIN KAGAKU KOGYO CO LTD | | J | BIC |
