| 2901 | ORCK | O R TRUCKING | | | SCAC3 |
| 2902 | ORCL | ORACLE TRANSPORT INC | | | SCAC4 |
| 2903 | ORCN | OIL RE-REFINING CO INC | | | SCAC4 |
| 2904 | ORCO | OHIO RIVER COMPANY, THE | | | SCAC3 |
| 2905 | ORCQ | ORICA LINES | | | SCAC3 |
| 2906 | ORCS | ORCAL TRANSPORT SERVICES INCORPORAT | | | SCAC3 |
| 2907 | ORCT | ORILLIA CITY TRUCKLINES LTD | | | SCAC3 |
| 2908 | ORCU | ORCA CONTAINER ASSET MANAGEMENT | | ZA | BIC |
| 2909 | ORCU | BSL TRANSPORT | | | PWRC |
| 2910 | ORCU | BSL Transport | | | RSRV |
| 2911 | ORCU | ORCA CONTAINER ASSET MANAGEMENT | | | SCAC4 |
| 2912 | ORCX | Oklahoma Refining Co. | 7/1937-4/1938 | | NAKINA |
| 2913 | ORCX | The Neatesfoot Oil Refineries Corp. | 7/1935 | | NAKINA |
| 2914 | ORCX | Oklahoma Refining Co. | Apr-38 | | NRHS |
| 2915 | ORCX | OKLAHOMA REFINING CO. | | | PWRC |
| 2916 | ORCZ | OHIO RIVER COMPANY | | | PWRC |
| 2917 | ORD | Cap. P.A. Hernando R. Ordonez Gutierrez | Callsign: Ordonez, | MEX | AVCODES |
| 2918 | ORD | Orange Air Services | | | ICAO1 |
| 2919 | ORDB | ORANGE DISTRIBUTION INC | | | SCAC3 |
| 2920 | ORDC | OROURKE DISTRIBUTING CO | | | SCAC3 |
| 2921 | ORDJ | ORANGE TRUCKING INC | | | SCAC3 |
| 2922 | ORDL | ORDER SHIPPING LIMITED | | | SCAC3 |
| 2923 | ORDL | ORDILLE, P N INC | | | SCAC4 |
| 2924 | ORDT | ORCUTT, DUANE TRUCKING | | | SCAC3 |
| 2925 | ORDW | ORDWAY TRUCKING | | | SCAC3 |
| 2926 | ORE | Greendale Aviation Company Ltd. | Callsign: Rekoya, | WAN | AVCODES |
| 2927 | ORE | Orange Aviation | | | ICAO1 |
| 2928 | OREC | OMEGA RECICLYNG | | | SCAC4 |
| 2929 | OREE | ORIENTAL EXPRESS | | | SCAC3 |
| 2930 | OREG | OREGRO SEEDS INC | | | SCAC4 |
| 2931 | OREK | OAK RIDGES ENTERPRISES INC | | | SCAC4 |
| 2932 | OREN | ORENELAS ARMENTA, PABLO | | | SCAC4 |
| 2933 | OREN | | City: Orenburg | RUS | TRAFFIC |
| 2934 | OREQ | OREGON TRUCK LINE | | | SCAC3 |
| 2935 | ORER | ORNELAS RIVERA, JOSE DE JESUS | | | SCAC4 |
| 2936 | ORET | OREGON TRANSFER CO | | | SCAC3 |
| 2937 | ORET | OREGON TRANSFER CO | | | SCAC4 |
| 2938 | OREU | ORIENT EXPRESS LLC | | RUS | BIC |
| 2939 | OREU | ORIENT EXPRESS LLC | | | SCAC4 |
| 2940 | OREX | Oregon Dept. of Agriculture | 1/1994-7/2005 (not listed) | | NAKINA |
| 2941 | OREX | REA Express, Inc. | added 10/1970; added 1/1971; eliminated 4/1974 | | NAKINA |
| 2942 | OREX | REA Express, owned and operated by Railway Express Agency, Inc. | eliminated 1/1971 | | NAKINA |
| 2943 | OREX | REA Express | added 10/1970 | | NAKINA |
| 2944 | OREX | Omaha Refining Co. | 8/1920 | | NAKINA |
| 2945 | OREX | REA Express | added 10/70; eliminated 4/74 | | NRHS |
| 2946 | OREX | Oregon Dept. of Agriculture | 1/94-7/2000 | | NRHS |
| 2947 | OREX | *OMAHA REFINING CO. | | | PWRC |
| 2948 | OREX | *REA EXPRESS, INC. (RAILWAY EXPRESS AGENCY, INC.) | | | PWRC |
| 2949 | OREX | +OREGON DEPARTMENT OF AGRICULTURE | | | PWRC |
| 2950 | OREX | Oregon Department of Agriculture | | | RSRV |
| 2951 | OREX | OREGON DEPARTMENT OF AGRICULTURE | | | SCAC4 |
| 2952 | OREY | OSPREY SHIPPING LLC | | | SCAC4 |
| 2953 | ORF | Royal Flight of Oman | IATA: RS, Callsign: Oman, Name change to Oman Royal Flight. | OM | AVCODES |
| 2954 | ORF | Oman Royal Flight | IATA: RS, Callsign: Oman, Name change from Royal Flight of Oman. | OM | AVCODES |
| 2955 | ORF | Oman Royal Flight | Callsign: Oman, Designator RS* recalled by IATA. Name change from Royal Flight of Oman. | OM | AVCODES |
| 2956 | ORF | Oman Royal Flight | | | ICAO1 |
| 2957 | ORFC | ORDWAY-FRAZER CARTAGE INC | | | SCAC3 |
| 2958 | ORFR | OVER-RIDE FREIGHT INC | | | SCAC3 |
| 2959 | ORFR | OROES FREIGHT SERVICE | | | SCAC4 |
| 2960 | ORFW | OREGON FREIGHTWAYS INC | | | SCAC3 |
| 2961 | ORG | Oriental Airlines (Gambia) Limited | Callsign: Oriegam, | WAG | AVCODES |
| 2962 | ORG | State Unitary Enterprise Orenburg Region, International Airport Orenburg | IATA: 07, Callsign: Orenavia, | RUS | AVCODES |
| 2963 | ORGB | ORANGEBURG TRUCKING INC | | | SCAC3 |
| 2964 | ORGB | ORGANIZACION EMBALSE | | | SCAC4 |
| 2965 | ORGC | ORANGE COURIER INC | | | SCAC4 |
| 2966 | ORGE | ORGANIC EXPRESS INC | | | SCAC4 |
| 2967 | ORGL | ORGILL INC | | | SCAC4 |
| 2968 | ORGM | OR GOURMET INC | | | SCAC4 |
| 2969 | ORGN | OREGON FOOD EXPRESS | | | SCAC3 |
| 2970 | ORGO | OREGON GLASS INC | | | SCAC3 |
| 2971 | ORGP | OREGON PROCESSING & RECOVERY CENTER | | | SCAC3 |
| 2972 | ORGQ | ORANGE COUNTY VAN & STORAGE CO INC | | | SCAC3 |
| 2973 | ORGR | ORTEGA, RENE A | | | SCAC4 |
| 2974 | ORGT | ORSCHELN, GREG TRANSPORTATION COMPA | | | SCAC3 |
| 2975 | ORGU | OREGON TEKNOLOJI HIZMETLERI AS | | TR | BIC |
| 2976 | ORGY | OR GALLERY | | | SCAC4 |
| 2977 | ORH | Orsha Air | Callsign: Orsha, | BY | AVCODES |
| 2978 | ORHT | OBRIEN, RALPH H TRUCKING CO | | | SCAC3 |
| 2979 | ORHX | Howard Tank Line | 1/1943-7/1965; eliminated 7/1966 | | NAKINA |
| 2980 | ORHX | Oscar R. Howard | 7/1923-1/1941 | | NAKINA |
| 2981 | ORHX | Oscar R. Howard | Apr-38 | | NRHS |
| 2982 | ORHX | Howard Tank Line | 1/52-7/65; eliminated 7/66 | | NRHS |
| 2983 | ORHX | HOWARD TANK LINE [OSCAR R. HOWARD] | | | PWRC |
| 2984 | ORHZ | OREVILLE HERITAGE RAILROAD COMMITTEE | | | PWRC |
| 2985 | ORI | Orion Air Pte. Ltd. | Callsign: Orion Air, | SY | AVCODES |
| 2986 | ORI | Orionair, S.L. | Callsign: Red Globe, Part of the TravelPlan group. Suspended operations on 04 June 2009. | E | AVCODES |
| 2987 | ORIC | ORLANDO INDUSTRIAL CONTRACTORS INC | | | SCAC3 |
| 2988 | ORIC | ONE TWO TWO SEVEN ZERO ZERO ONE (12 | | | SCAC4 |
| 2989 | ORID | ORION DELIVERY SERVICE INC | | | SCAC3 |
| 2990 | ORID | ORTIZ ORTIZ, IDELIO | | | SCAC4 |
| 2991 | ORIE | ORIENT TRUCKING AND CONSTRUCTION CO | | | SCAC3 |
| 2992 | ORIG | ORIGINAL HALL-LANE MOVING & STORAGE | | | SCAC3 |
| 2993 | ORIL | ORIOLE CHEMICAL CARRIERS INC | | | SCAC3 |
| 2994 | ORIN | ORIENTAL MOVERS INC | | | SCAC3 |
| 2995 | ORIO | Orione S.r.L., Tito | | I | TRAFFIC |
| 2996 | ORION | F.H.U. ORION Kolej Krzysztof Warchoł | | PL | VKM |
| 2997 | ORIP | ORIENT PACIFIC | | | SCAC3 |
| 2998 | ORIT | ORIOLE TRUCKING INC | | | SCAC3 |
| 2999 | ORIU | VINCI & CAMPAGNA SPA | | I | BIC |
| 3000 | ORIY | ORION ENERGY CORP | | | SCAC4 |
