| 1 | HCX | Aerocom Aviation Oy t/a Helsinki Citycopter | Callsign: City Copter, | FIN | AVCODES |
| 2 | HCX | Hallet and Carey Ltd. | added 1/1953; eliminated 10/1953 | | NAKINA |
| 3 | HCX | Merchants Despatch Transportation Corp. | 1/1941-1/1950 | | NAKINA |
| 4 | HCX | Hardwood Chemical Co. (General American Transportation Corp.) | 7/1935 | | NAKINA |
| 5 | HCX | Hallet and Carey Ltd. | added 1/53; eliminated 10/53 | | NRHS |
| 6 | HCX | *MERCHANTS DESPATCH TRANSPORTATION CORP. | | | PWRC |
| 7 | HCX | *HALLET & CAREY LTD. | | | PWRC |
| 8 | HCXC | HOC TRANSPORT COMPANY | | | SCAC4 |
| 9 | HCXN | HCS TRANSPORTATION | | | SCAC4 |
