| 1 | CYM | Compass Airlines | IATA: YM, Callsign: Compair, Founded in 1990 ceased operations in 1991. Restarted operations in 1992 and finally ceased operations on 22 March 1993. | AUS | AVCODES |
| 2 | CYM | Cymru Wales Airways | Callsign: Snowdon, Ceased operations | GB | AVCODES |
| 3 | CYM | Airways International Cymru Ltd. | Callsign: Welshair, Ceased operations | GB | AVCODES |
| 4 | CYMA | COUNTY MOVING OF ABILENE INC | | | SCAC4 |
| 5 | CYMC | CLASSY-MAC INC | | | SCAC3 |
| 6 | CYMD | COUNTRY MEADOWS | | | SCAC4 |
| 7 | CYME | CYMEON SHIPPING CORPORATION | | | SCAC3 |
| 8 | CYME | CYMER TRANSPORT INC | | | SCAC4 |
| 9 | CYMG | CONSTANTLY MOVING | | | SCAC3 |
| 10 | CYMH | CAREYS MOBILE HOME TOWING | | | SCAC3 |
| 11 | CYMI | CAYMAN ISLAND SHIPPING INC. | | | SCAC3 |
| 12 | CYMI | CAYMAN ISLANDS SHIPPING LTD | | | SCAC4 |
| 13 | CYMI | CONTROL Y MONTAJES INDUSTRIALES CYMI S.A. | | ES | VKM |
| 14 | CYMK | CLAY-MOATE EXPRESS TRUCKING INC | | | SCAC4 |
| 15 | CYML | CYCLADIC MARINE LTD | | | SCAC3 |
| 16 | CYML | CYPRUS MARITIME COMPANY LIMITED | | | SCAC4 |
| 17 | CYMN | CANTRELL REFINERY SALES AND TRANSPO | | | SCAC4 |
| 18 | CYMQ | COY MOVING & STORAGE | | | SCAC3 |
| 19 | CYMS | CAPITAL CITY MOVING & STORAGE | | | SCAC3 |
| 20 | CYMT | COUNTRYMAN TRUCKING LTD | | | SCAC4 |
| 21 | CYMV | COYNE MOTOR SERVICE INC | | | SCAC4 |
| 22 | CYMW | CHRYSSI MARITIME COMPANY | | | SCAC4 |
| 23 | CYMX | Cytec Carbon Fibers LLC | added 10/2003; 7/2005 | | NAKINA |
| 24 | CYMX | CYTEC CARBON FIBERS LLC | | | PWRC |
| 25 | CYMX | CYTEC CARBON FIBERS LLC | | | SCAC4 |
| 26 | CYMX | Cumberland Mine Railroad | | USA | TRAFFIC |
