| 1 | GR | Aurigny Air Services Limited | ICAO: AUR, Callsign: Ayline, IATA Prefix: 924, | GBG | AVCODES |
| 2 | GR | Gemini Air Cargo LLC | ICAO: GCO, Callsign: Gemini, IATA Prefix: 358, Ceased operations on 12 August 2008 | USA | AVCODES |
| 3 | GR | Grand Rapids Eastern R.R., Inc. | 1/1994; added 10/1994; 7/2000; eliminated 4/2005; 7/2005 | | NAKINA |
| 4 | GR | Grasse River R.R. | 4/1938-7/1965 | | NAKINA |
| 5 | GR | Grasse River R.R. Corp. | 7/1923-7/1936 | | NAKINA |
| 6 | GR | Grasse River R.R. | 4/38-7/65 | | NRHS |
| 7 | GR | Grand Rapids Eastern R.R., Inc. | 1/94; added 10/94; 7/2000 | | NRHS |
| 8 | GR | GRAND RAPIDS EASTERN RAILROAD INC. [GRASSE RIVER RR] | | | PWRC |
| 9 | GR | Grand Rapids Eastern Railroad | | | RSRV |
| 10 | GR | GRAND RAPIDS EASTERN RAILROAD INC | | | SCAC4 |
| 11 | GR | Chemins de fer de Géorgie | | GE | VKM |
| 12 | GRA | Great American Airways | Callsign: Great American, AOC revoked on 13 April 1997. | USA | AVCODES |
| 13 | GRA | Guardian Air Asset Management (Pty) Ltd. | Callsign: Flex, | ZA | AVCODES |
| 14 | GRA | Great American Airways | | | ICAO1 |
| 15 | GRA | GRAY LINE COMPANY, THE | | | SCAC4 |
| 16 | GRA | Great American Airways | Real: GRA / MV | USA | TRAFFIC |
| 17 | GRAA | GRASS, M E & SONS INC | | | SCAC4 |
| 18 | GRAF | Gräf & Stift | since 2002 subsidiary of MAN | A | TRAFFIC |
| 19 | Graf MEC | Grafschafter Modell-Eisenbahnclub e.V. | Nordhorn | D | privat-bahn.de |
| 20 | GRAG | Ing. Greuter AG | | CH | VKM |
| 21 | GRAH | GREAT AMERICAN MOVERS (A CORPORATIO | | | SCAC4 |
| 22 | GRAJ | GARCIA ALEGRIA, ROBERTO | | | SCAC4 |
| 23 | GRAK | GARCHA, D TRUCKING LTD | | | SCAC4 |
| 24 | GRAM | GRAHAM SHIP BY TRUCK COMPANY | | | SCAC1 |
| 25 | GRAN | Greater Anglia | | GB | TRAFFIC |
| 26 | GRAN | Bauunternehmung Granit GmbH | | AT | VKM |
| 27 | GRAQ | GRANITE CREATIONS INC | | | SCAC4 |
| 28 | GRAS | GROSHELL TRANSPORTATION SERVICES IN | | | SCAC4 |
| 29 | GRAS | JKP GRAS Sarajevo (Javno Komunalno Preduzeće – Gradski Saobraćaj Sarajevo) | | BIH | TRAFFIC |
| 30 | GRAS | Grenland rail AS | | NO | VKM |
| 31 | GRAV | GUTIERREZ AVALOS, ALFONSO | | | SCAC4 |
| 32 | GRAW | GRAY, GARY W | | | SCAC1 |
| 33 | GRAX | Grax Corp. | added 7/1965; 7/1965-10/1966; eliminated 7/1968 | | NAKINA |
| 34 | GRAX | Grax Corp. | added 7/65; 7/65-10/66; eliminated 7/68 | | NRHS |
| 35 | GRAX | GRAX CORP. | | | PWRC |
| 36 | GRAX | GRAYMONT (PA) INC | | | SCAC4 |
| 37 | GRAY | Gray Coach Lines | | CDN | TRAFFIC |
| 38 | GRB | Phoenix Air Group, Inc. | IATA: PH, Callsign: Gray Bird, ICAO Designator changed from PHA. | USA | AVCODES |
| 39 | GRBA | GRANIT DIRECT | | | SCAC4 |
| 40 | GRBC | GIBLETT FARM & RANCH LTD | | | SCAC4 |
| 41 | GRBH | G R T TRUCKING | | | SCAC4 |
| 42 | GRBI | GARAGE RENE BERTRAND INC | | | SCAC4 |
| 43 | GRBJ | GRANTON TRAILERS LIMITED | | | SCAC4 |
| 44 | GRBL | GREENBELT TRANSPORT | | | SCAC4 |
| 45 | GRBP | GRACE ROAD LINES LTD | | | SCAC4 |
| 46 | GRBR | GFI TRANSPORT.COM | | | SCAC4 |
| 47 | GRBT | GRAINBELT TRANSPORT LTD | | | SCAC4 |
| 48 | GRBU | GOODRICH MARITIME PRIVATE LIMITED | | IND | BIC |
| 49 | GRBV | GREAT NORTHERN MODELS | | | SCAC4 |
| 50 | GRC | Grace Flight Of America, Inc. | Callsign: Grace Flight, | USA | AVCODES |
| 51 | GRC | GLASGOW RAILWAY CO. | | | PWRC |
| 52 | GRC | Ghana Railway Corporation | | GH | TRAFFIC |
| 53 | GRCC | GRANITE CONSTRUCTION COMPANY | | | SCAC4 |
| 54 | GRCF | GARCIA ASTORGA, ABEVARDO | | | SCAC4 |
| 55 | GRCG | GREEN CHARTERING ASMIND NORWAY | | | SCAC1 |
| 56 | GRCG | GREEN CHARTERING A/S | | | SCAC4 |
| 57 | GRCI | GRACE TRANSPORT INC | | | SCAC4 |
| 58 | GRCJ | GARCIA CORTEZ, JOEL SA DE CV | | | SCAC4 |
| 59 | GRCK | GARCIA, F TRANSPORT | | | SCAC4 |
| 60 | GRCL | GRACE LINES INC | | | SCAC4 |
| 61 | GRCM | GREEN & CHAPMAN INC | | | SCAC4 |
| 62 | GRCN | GRACE TRANSPORT INC | | | SCAC4 |
| 63 | GRCR | GARCIA RECYCLING CENTER & METALS IN | | | SCAC4 |
| 64 | GRCU | BORCHARD LINES LTD | | GB | BIC |
| 65 | GRCU | GRACECHURCH CONTAINER LINE LTD | | | SCAC4 |
| 66 | GRCV | GREEN LINE EXPRESS SERVICES INC | | | SCAC4 |
| 67 | GRCX | Granite Rock Co. | added 1/1971; 1/1975-1/1994; 7/2000-7/2005 (not listed) | | NAKINA |
| 68 | GRCX | Warren Petroleum Corp. | 4/1961 | | NAKINA |
| 69 | GRCX | Gulf Oil Corp. | eliminated 7/1961 | | NAKINA |
| 70 | GRCX | Gulf Refining Co. | 8/1920-7/1935 | | NAKINA |
| 71 | GRCX | Gulf Oil Corp. | 7/1937-10/1957 | | NAKINA |
| 72 | GRCX | Gulf Oil Corp. | 4/38-10/57 | | NRHS |
| 73 | GRCX | Warren Petroleum Corp. | Apr-61 | | NRHS |
| 74 | GRCX | Granite Rock Co. | added 1/71; 1/75-7/2000 | | NRHS |
| 75 | GRCX | *GULF OIL CORP. [WARREN PETROLEUM CORP.; GULF REFINING CO.] | | | PWRC |
| 76 | GRCX | +GRANITE ROCK CO. | | | PWRC |
| 77 | GRCX | Granite Rock | | | RSRV |
| 78 | GRCX | GRANITE ROCK CO. | | | SCAC4 |
| 79 | GRCZ | GRANITE CITY STEEL | | | PWRC |
| 80 | GRD | National Grid Co plc | Callsign: Grid, | GB | AVCODES |
| 81 | GRD | National Grid | | | ICAO1 |
| 82 | GRDB | GAEBEL MICHIGAN MOVERS INC | | | SCAC4 |
| 83 | GRDD | GARDNER OIL INC | | | SCAC4 |
| 84 | GRDE | GALLEGOS ROMAN, DORA ALICIA | | | SCAC4 |
| 85 | GRDI | GUERRERO, ROLANDO INC | | | SCAC4 |
| 86 | GRDK | GRUPO INDUSTRIAL DE SISTEMA DE CONF | | | SCAC4 |
| 87 | GRDL | GORDON LOGISTICS LLC | | | SCAC4 |
| 88 | GRDN | GARDNER GAS HAULING INC | | | SCAC4 |
| 89 | GRDO | GRAND UNION CO | | | SCAC4 |
| 90 | GRDQ | GREEN, DENNIS & SONS | | | SCAC4 |
| 91 | GRDS | GERALDOS TRUCKING CORP | | | SCAC4 |
| 92 | GRDT | GARDNER TRANSPORT LLC | | | SCAC4 |
| 93 | GRDU | TOUAX GROUP | | F | BIC |
| 94 | GRDU | GOLD CONTAINER CORP | | | SCAC4 |
| 95 | GRDW | GRANT, DAVE, HAY, INC | | | SCAC1 |
| 96 | GRDW | GRANT, DAVE R HAY INC | | | SCAC4 |
| 97 | GRDX | Grand River Dam Authority | added 10/1978; eliminated 4/1979; added 1/1981; 1/1994-7/2000; eliminated 7/2001; 7/2005 (not listed) | | NAKINA |
| 98 | GRDX | Grand River Dam Authority | added 10/78; eliminated 4/79; added 1/81; 1/94-7/2000; eliminated 7/2001 | | NRHS |
| 99 | GRDX | GRAND RIVER DAM AUTHORITY | | | PWRC |
| 100 | GRDX | Grand River Dam Authority | | | RSRV |
