| 1 | YK | Kibris Turk Hava Yollari | ICAO: KYV, Callsign: AirKibris, IATA Prefix: 056, Suspended operations at 23:59L on 21 June 2010. Designator YK reinstated by IATA | TR | AVCODES |
| 2 | YK | Horizon Airlines Pty Ltd. | ICAO: HZN, IATA designator changed to KH*. Name changed from International Aviation Pty. Ltd. | AUS | AVCODES |
| 3 | YK | International Aviation Pty. Ltd. | Name changed to Horizon Airlines Pty Ltd. | AUS | AVCODES |
| 4 | YK | Avia Traffic Company LLC | ICAO: AVJ, Callsign: Atomic, IATA designator changed from Z7 | KS | AVCODES |
| 5 | YKAL | YUKON ALASKA TRANSPORT | | | SCAC4 |
| 6 | YKCG | YUKON CARGO | | | SCAC4 |
| 7 | YKCO | YAKIMA CO-OPERATIVE ASSOCIATION | | | SCAC4 |
| 8 | YKLC | YORKIE LLC | | | SCAC4 |
| 9 | YKMP | YOAKUM PACKING CO | | | SCAC4 |
| 10 | YKR | Yorkrail, Inc. | added 10/1989; 1/1994; eliminated 4/2000 | | NAKINA |
| 11 | YKR | York Ry. Co. | added 4/2000; 7/2000-7/2005 | | NAKINA |
| 12 | YKR | Yorkrail, Inc. | added 10/89; 1/94; eliminated 4/2000 | | NRHS |
| 13 | YKR | York Ry. Co. | added 4/2000; 7/2000 | | NRHS |
| 14 | YKR | YORK RAILWAY [YORKRAIL, INC.] | | | PWRC |
| 15 | YKR | Yorkrail (York Railway) | | | RSRV |
| 16 | YKR | Yorkrail, Inc. | | USA | TRAFFIC |
| 17 | YKSN | YODER, KEN AND SONS | | | SCAC4 |
| 18 | YKT | YANKEE TRAILS INC | | | SCAC4 |
| 19 | YKTC | YORK TRANSPORT CORP | | | SCAC4 |
| 20 | YKTK | YORKE, WILF TRUCKING | | | SCAC4 |
| 21 | YKTL | YOUNG-KO TRANS CO LTD | | | SCAC4 |
| 22 | YKTP | Y K TRANSPORT | | | SCAC4 |
| 23 | YKTX | Y2K PRIVATE MARK TEST | | | SCAC4 |
