| 1 | GRH | Green Hills Aviation Ltd. | Callsign: Green Hills, | USA | AVCODES |
| 2 | GRHA | GRAHAM, KENNETH TRUCKING INC | | | SCAC4 |
| 3 | GRHH | GREGS HOG HAULING INC | | | SCAC4 |
| 4 | GRHI | GRJH INC | | | SCAC4 |
| 5 | GRHJ | GARRISON, H J OIL COMPANY INC | | | SCAC4 |
| 6 | GRHK | GRAHAM TRUCKING, INC | | | SCAC1 |
| 7 | GRHN | GARAGE CHRISTIAN QUELLET LTEE | | | SCAC4 |
| 8 | GRHP | GRESHAM PETROLEUM CO | | | SCAC4 |
| 9 | GRHR | GARZA FALCON, FELIPE EDUARDO | | | SCAC4 |
| 10 | GRHT | GRAHAM TRANSPORTATION LTD | | | SCAC4 |
| 11 | GRHV | GRANT, J S TRANSPORT | | | SCAC4 |
| 12 | GRHW | GINGRICH WOODCRAFT INC | | | SCAC4 |
| 13 | GRHX | Gulf Railcar, Inc. | added 1/1991; eliminated 7/1992; 1/1994 (not listed) | | NAKINA |
| 14 | GRHX | Gulf Railcar, Inc. | added 1/91; eliminated 7/92; 1/94 | | NRHS |
| 15 | GRHX | GULF RAILCAR, INC. | | | PWRC |
