| 1001 | OFCP | ORNELAS FONTES, CRISPINA | | | SCAC4 |
| 1002 | OFCS | OFFERLE COOPERATIVE & SUPPLY CO | | | SCAC3 |
| 1003 | OFCS | ONEIDA FREIGHT CARRIERS INC | | | SCAC4 |
| 1004 | OFCT | OVERLAND FREIGHT CORPORATION | | | SCAC4 |
| 1005 | OFCW | OLDENDORFF CARRIERS | | | SCAC4 |
| 1006 | OFCX | Residco | added 7/1987; 1/1994-7/2000; eliminated 10/2004; 7/2005 (not listed); added 7/2008 | | NAKINA |
| 1007 | OFCX | Ortner Freight Car Co. | added 10/1967; 4/1970-1/1980; eliminated 7/1987 | | NAKINA |
| 1008 | OFCX | Ortner Freight Car Co. | added 10/67; 4/70-1/80; eliminated 7/87 | | NRHS |
| 1009 | OFCX | Residco | added 7/87; 1/94-7/2000 | | NRHS |
| 1010 | OFCX | *ORTNER FREIGHT CAR CO. | | | PWRC |
| 1011 | OFCX | +RESIDCO | | | PWRC |
| 1012 | OFCX | Ortner Freight Car | | | RSRV |
| 1013 | OFCX | RESIDCO | | | SCAC4 |
| 1014 | OFDC | OLSON, FRED CO INC | | | SCAC3 |
| 1015 | OFDC | OFISDECO | | | SCAC4 |
| 1016 | OFDL | OSBORN & ASSOCIATES OF FOND DU LAC | | | SCAC4 |
| 1017 | OFDT | OILFIELD TRUCKING & TRANSPORTATION | | | SCAC3 |
| 1018 | OFDT | OMSTEAD FOODS LTD | | | SCAC4 |
| 1019 | OFEC | OVERLAND SYSTEMS INC | | | SCAC4 |
| 1020 | OFEG | ONE FOUR EIGHT SEVEN FIVE THREE FOU | | | SCAC4 |
| 1021 | OFEI | ONE FIVE EIGHT NINE SIX TWO ONE (15 | | | SCAC4 |
| 1022 | OFEN | OFFEN INC | | | SCAC3 |
| 1023 | OFER | ONE FOUR EIGHT THREE FOUR NINE TWO | | | SCAC4 |
| 1024 | OFES | ONE FOUR EIGHT SEVEN FIVE | | | SCAC4 |
| 1025 | OFET | ONE FOUR EIGHT TWO SEVEN FOUR (1482 | | | SCAC4 |
| 1026 | OFF | Challenge International Airlines | Callsign: Challenge Air, | USA | AVCODES |
| 1027 | OFF | Challenge International Airlines | | | ICAO1 |
| 1028 | OFFC | OFFSHORE CRANE & SERVICE COMPANY, INC | | | SCAC3 |
| 1029 | OFFD | OFF DOCK UNLIMITED | | | SCAC3 |
| 1030 | OFFH | OFFENHEISER INC | | | SCAC4 |
| 1031 | OFFI | OPPORTUNITY FAST FREIGHT INC | | | SCAC3 |
| 1032 | OFFK | ONE FIVE FIVE SIX EIGHT FIVE FOUR ( | | | SCAC4 |
| 1033 | OFFL | OFFICIAL FAST FREIGHT LLC | | | SCAC4 |
| 1034 | OFFM | OFFICE MOVERS INC | | | SCAC3 |
| 1035 | OFFM | OFFICE MOVERS INC | | | SCAC4 |
| 1036 | OFFR | OHIO FAST FREIGHT, INC | | | SCAC3 |
| 1037 | OFFR | ONE FOUR FIVE FIVE FOUR NINE TWO (1 | | | SCAC4 |
| 1038 | OFFT | OFFMOR TRUCKING INC | | | SCAC4 |
| 1039 | OFFU | CARU CONTAINERS BV | | NL | BIC |
| 1040 | OFFU | CONTAINER COMPANY AMSTERDAM BV | | | SCAC4 |
| 1041 | OFFV | ONE FIVE FIVE THREE SIX SIX NINE (1 | | | SCAC4 |
| 1042 | OFFY | OLD FRONTIER FAMILY INC | | | SCAC4 |
| 1043 | OFGC | OSKALOOSA FEED & GRAIN CO | | | SCAC3 |
| 1044 | OFGX | The Osage Gasoline Corp. | 7/1923 | | NAKINA |
| 1045 | OFGX | OSAGE GASOLINE CORP. | | | PWRC |
| 1046 | OFII | OVERSEAS FINANCIAL INSTITUTE INC | | | SCAC4 |
| 1047 | OFIN | OMEGA FREIGHT INC | | | SCAC3 |
| 1048 | OFIO | OWENS FUELS INC OF WELLINGTON | | | SCAC4 |
| 1049 | OFIQ | OVERNIGHT FREIGHT INC | | | SCAC4 |
| 1050 | OFIT | OVERLAND FREIGHT INTERNATIONAL(OFI) | | | SCAC4 |
| 1051 | OFIX | Olie Fabrieken Institute (Java Coconut Oil Co., Ltd. of New York) | 8/1920-7/1923 | | NAKINA |
| 1052 | OFIX | JAVA COCONUT OIL CO. LTD. OR NEW YORK [OLIE FABRIEKEN INSTITUTE] | | | PWRC |
| 1053 | OFJS | OHARA, F J & SONS INC | | | SCAC4 |
| 1054 | OFK | OFEK | | IL | AVCODES |
| 1055 | OFKX | Witco Chemical Corp. | added 1/1969; 4/1970-1/1975 | | NAKINA |
| 1056 | OFKX | Witco Chemical Co., Inc. | added 1/1967; eliminated 1/1969 | | NAKINA |
| 1057 | OFKX | Koch Tank Line, Inc. | 7/1937-10/1966; eliminated 1/1967 | | NAKINA |
| 1058 | OFKX | Otto Koch | 7/1930 | | NAKINA |
| 1059 | OFKX | Koch Tank Line | 7/1932-7/1935 | | NAKINA |
| 1060 | OFKX | Koch Tank Line, Inc. | 4/38-10/66; eliminated 1/67 | | NRHS |
| 1061 | OFKX | Witco Chemical Co., Inc. | added 1/67; eliminated 1/69 | | NRHS |
| 1062 | OFKX | Witco Chemical Corp. | added 1/69; 4/70-1/75 | | NRHS |
| 1063 | OFKX | WITCO CHEMICAL [KOCH TANK LINE; OTTO KOCH] | | | PWRC |
| 1064 | OFKX | KOCH TANK LINE | | | SCAC3 |
| 1065 | OFL | Open Flight | Callsign: Open Flight, | F | AVCODES |
| 1066 | OFLA | OPTIMAL FREIGHT LLC | | | SCAC4 |
| 1067 | OFLC | OSG FREIGHT LINES LLC | | | SCAC4 |
| 1068 | OFLD | OTTOR FREIGHTWAYS LIMITED | | | SCAC3 |
| 1069 | OFLL | OVERLAND FREIGHT LINES LTD | | | SCAC3 |
| 1070 | OFLM | OILFIELD MAINTENANCE COMPANY | | | SCAC3 |
| 1071 | OFLN | OSCAR FREIGHT LINE | | | SCAC3 |
| 1072 | OFLW | OVERFLOW ULTRA LOGISTICS | | | SCAC4 |
| 1073 | OFM | Oasis Flight Malta Ltd | | M | AVCODES |
| 1074 | OFMK | OC FLOCK MANAGEMENT | | | SCAC4 |
| 1075 | OFMO | OLSEN & FIELDING MOVING SERVICES | | | SCAC3 |
| 1076 | OFMO | OLSEN & FIELDING MOVING SERVICES | | | SCAC4 |
| 1077 | OFMS | OTT, FRED M & SONS INC | | | SCAC3 |
| 1078 | OFNA | ONE FIVE FIVE FIVE NINE THREE EIGHT | | | SCAC4 |
| 1079 | OFNC | ONE FOUR NINE SEVEN ONE THREE (1497 | | | SCAC4 |
| 1080 | OFNE | ONE FOUR NINE EIGHT TWO ONE ONE (14 | | | SCAC4 |
| 1081 | OFNL | ONE FIVE NINE ZERO EIGHT TWO EIGHT | | | SCAC4 |
| 1082 | OFNP | OFFEN PETROLEUM INC | | | SCAC4 |
| 1083 | OFNR | ONE ELEVEN FARMS & NURSERIES | | | SCAC4 |
| 1084 | OFNS | ONE TWO THREE FIVE FOUR NINE SIX (1 | | | SCAC4 |
| 1085 | OFOA | ONE FOUR ONE THREE THREE | | | SCAC4 |
| 1086 | OFOB | OLSON FARMS OF BASSWOOD INC | | | SCAC4 |
| 1087 | OFOE | ONE FIVE ONE EIGHT ONE SEVEN (15181 | | | SCAC4 |
| 1088 | OFOF | ONE FIVE ONE FOUR ZERO EIGHT (15140 | | | SCAC3 |
| 1089 | OFOG | ONE FOUR ONE (141) FREIGHT SOLUTION | | | SCAC4 |
| 1090 | OFOH | ONE FIVE ONE EIGHT FOUR TWO THREE ( | | | SCAC4 |
| 1091 | OFOO | ONE FOUR ONE TWO ONE SIX FIVE (1412 | | | SCAC4 |
| 1092 | OFOQ | ONE FIVE ONE FOUR THREE FOUR TWO (1 | | | SCAC4 |
| 1093 | OFOS | ONE FOUR ONE NINE SIX FOUR EIGHT (1 | | | SCAC4 |
| 1094 | OFOX | Residco | added 7/1988; 1/1994-7/2000; eliminated 10/2004; 7/2005 (not listed); added 7/2008 | | NAKINA |
| 1095 | OFOX | Residco | added 7/88; 1/94-7/2000 | | NRHS |
| 1096 | OFOX | RESIDCO | | | PWRC |
| 1097 | OFOX | Residco | | | RSRV |
| 1098 | OFPC | OGDEN FOOD PRODUCTS CORPORATION | | | SCAC3 |
| 1099 | OFPR | OREGON FRUIT PRODUCTS CO | | | SCAC3 |
| 1100 | OFPR | OREGON FRUIT PRODUCTS CO | | | SCAC4 |
