| 1 | YD | State Enterprise Gomelavia | ICAO: GOM, Callsign: Gomel, Name changed to Republican Aviation Unitary Enterprise | BY | AVCODES |
| 2 | YD | Synergy Aviation Ltd. | ICAO: SYG, Callsign: Synergy, IATA Prefix: 259, | GB | AVCODES |
| 3 | YD | Air Taxi Klagenfurt t/a Transalp Air | | A | AVCODES |
| 4 | YDC | YANKEE DOT CORP. | | | PWRC |
| 5 | YDC | Yankeetown Docks Corporation | | USA | TRAFFIC |
| 6 | YDCS | YAZICI DEMIR CELIK SANAYI VE TURIZM | | | SCAC4 |
| 7 | YDCX | Yankeetown Dock Corp. | added 7/1979; 1/1980; eliminated 1/1980 | | NAKINA |
| 8 | YDCX | Peabody Coalsales Co. | added 7/2005; 7/2005 | | NAKINA |
| 9 | YDCX | Yankeetown Dock Corp. | added 7/79; 1/80; eliminated 1/80 | | NRHS |
| 10 | YDCX | *YANKEETOWN DOCK CORP. | | | PWRC |
| 11 | YDCX | +PEABODY COALSALES CO. | | | PWRC |
| 12 | YDCX | PEABODY COALSALES COMPANY | | | SCAC4 |
| 13 | YDHR | York Durham Heritage Railway | | | RSRV |
| 14 | YDHR | York-Durham Heritage Railway | | CDN | TRAFFIC |
| 15 | YDIS | YANEZ, DIMAS | | | SCAC4 |
| 16 | YDKY | YACUCHA, DEAN KELLY | | | SCAC4 |
| 17 | YDLA | YARDA LUPITA | | | SCAC4 |
| 18 | YDLC | YVES DELORME INC | | | SCAC4 |
| 19 | YDRJ | YODER, JOSEPH | | | SCAC4 |
| 20 | YDRT | YODER TRUCKING | | | SCAC4 |
| 21 | YDSI | YESTERDAY DELIVERY SERVICE INC | | | SCAC4 |
| 22 | YDTI | YODER TRANSPORTATION INC | | | SCAC4 |
| 23 | YDTK | YELLOW DOG TRUCKING LTD | | | SCAC4 |
| 24 | YDWH | YOUNG, D W HAULAGE INC | | | SCAC4 |
| 25 | YDXU | PT INDONESIA GUANG CHING NICKEL AND STAINLESS STEEL IND | | RI | BIC |
