| 1 | UY | Cameroon Airlines | ICAO: UYC, Callsign: Cam-Air, IATA Prefix: 604, Ceased Operations in March 2008 | CAM | AVCODES |
| 2 | UY | Air Caucasus | ICAO: CSG, IATA Prefix: 049, Commenced operations in August 2013. Ceased operations during 2014. | GE | AVCODES |
| 3 | UY | Sky Prime Aviation Services | ICAO: SPD, Callsign: Sky Prime, IATA designator UY recalled. | SA | AVCODES |
| 4 | UYA | Flight Alaska, Inc., d/b/a Yute Air Alaska, Inc. | IATA: 4Y, Callsign: Yute Air, Merged operations in Ravn Alaska on 05 March 2017. | USA | AVCODES |
| 5 | UYAF | Uruguayan Air Force | Fuerza Aérea Uruguaya | ROU | TRAFFIC |
| 6 | UYAK | UNIEXPRESS SYSTEMS INC | | | SCAC4 |
| 7 | UYC | Cameroon Airlines | IATA: UY, Callsign: Cam-Air, IATA Prefix: 604, Ceased Operations in March 2008 | CAM | AVCODES |
| 8 | UYC | Cameroon Airlines | IATA: UY | | ICAO1 |
| 9 | UYHI | UP YORK HILT INC | | | SCAC4 |
| 10 | UYLU | UNITED YUGOSLAV LINES (KERR STEAMSHIP CO AGENTS) | | | PWRC |
| 11 | UYLU | United Yugoslav Lines | | | RSRV |
| 12 | UYLZ | UNITED YUGOSLAV LINES | | | PWRC |
| 13 | UYLZ | United Yugoslav Lines | | | RSRV |
| 14 | UYLZ | UNITED YUGOSLAV LINE | | | SCAC4 |
| 15 | UYSN | UNYSON LOGISTICS | | | SCAC4 |
| 16 | UYTL | UMPHREY TRUCK LINES INC | | | SCAC4 |
