| 3201 | OS | Ontario Southland Ry. Inc. | 7/2005 | | NAKINA |
| 3202 | OS | ONTARIO SOUTHLAND RWY., INC. | | | PWRC |
| 3203 | OS | ONTARIO SOUTHLAND RAILWAY INC | | | SCAC4 |
| 3204 | OSA | Aero Astra | Callsign: Rostra, | MEX | AVCODES |
| 3205 | OSA | Open Sky Aviation | | | ICAO1 |
| 3206 | OSAA | OSARPA | | | SCAC4 |
| 3207 | OSAC | OMEGA SOLUTIONS TRANSPORT INC | | | SCAC4 |
| 3208 | OSAG | OSAGE OIL & TRANSPORTATION INC | | | SCAC3 |
| 3209 | OSAG | OSPECA LOGISTICS MANAGEMENT TRANSPO | | | SCAC4 |
| 3210 | OSAG | Osterwalder St. Gallen AG | | CH | TRAFFIC |
| 3211 | OSAG | Osterwalder St. Gallen AG | | CH | VKM |
| 3212 | OSAI | ORINOCO SHIPPING AGENCIES INC | | | SCAC3 |
| 3213 | OSAKAB | Osaka Bus Co. | | J | TRAFFIC |
| 3214 | OSAM | Osaka Monorail | | J | TRAFFIC |
| 3215 | OSAP | OCEANA SHIPPING AG | | | SCAC4 |
| 3216 | OSAR | OSAR TRUCKING CO, INC | | | SCAC3 |
| 3217 | OSAW | OAKLEY SUB ASSEMBLY WINDSOR | | | SCAC4 |
| 3218 | OSB | Osob Airlines | Callsign: Osob, | SO | AVCODES |
| 3219 | OSB | Ortenau S-Bahn GmbH | Offenburg (SWEG-Tochter) | D | privat-bahn.de |
| 3220 | OSB | Ortenau-S-Bahn | | D | TRAFFIC |
| 3221 | OSB | Ortenau-S-Bahn | | DE | VKM |
| 3222 | OSBA | OSBORNE TRUCKING CO INC | | | SCAC4 |
| 3223 | OSBC | OSBORNES TRUCKING INC | | | SCAC3 |
| 3224 | OSBC | OCEANEXPRESS | | | SCAC4 |
| 3225 | OSBD | OSBURN, DALE INC | | | SCAC3 |
| 3226 | OSBD | OSBORNE PROPELLERS LTD | | | SCAC4 |
| 3227 | OSBE | OSBORNES TRUCKING INC | | | SCAC4 |
| 3228 | OSBI | OSTERBUR TRUCKING INC | | | SCAC3 |
| 3229 | OSBJ | OSBORNE, J R INC | | | SCAC3 |
| 3230 | OSBN | OSBORN CARIERS INC | | | SCAC3 |
| 3231 | OSBN | OVERSEAS BOSTON LLC | | | SCAC4 |
| 3232 | OSBO | OSBORN TRUCKING INC | | | SCAC3 |
| 3233 | OSBO | OSBORNE LOGISTICS LLC | | | SCAC4 |
| 3234 | OSBP | OFF-SET BASS DRUM PEDAL | | | SCAC4 |
| 3235 | OSBS | OSBORN & SON TRUCKING CO, INC | | | SCAC3 |
| 3236 | OSBS | Osborn & Son Trucking Co Inc. | | USA | TRAFFIC |
| 3237 | OSBT | OSBORNE TRUCKING CO INC | | | SCAC3 |
| 3238 | OSBV | OVET SHIPPING BV | | | SCAC4 |
| 3239 | OSC | OneSky Aviation Services S.p.a. (OneSky Chile) | Callsign: Uncielo, | RCH | AVCODES |
| 3240 | OSC | Osaka Municipal Transportation Bureau | | J | TRAFFIC |
| 3241 | OSCA | ONE STOP CRITICAL | | | SCAC4 |
| 3242 | OSCC | OMNI/SOUTHEASTERN CHEMICAL CO INC | | | SCAC3 |
| 3243 | OSCD | OCEAN STATE COURIER AND DELIVERY IN | | | SCAC3 |
| 3244 | OSCD | ONE SEVEN TWO ZERO SIX TWO (172062) | | | SCAC4 |
| 3245 | OSCH | OSTLUND CHEMICAL CO | | | SCAC3 |
| 3246 | OSCH | OSCAR SHIPMANAGEME | | | SCAC4 |
| 3247 | OSCH | | City: Oschersleben | D | TRAFFIC |
| 3248 | OSCI | OSULLIVAN CARTAGE INC | | | SCAC3 |
| 3249 | OSCK | OXYGEN SERVICE COMPANY INC | | | SCAC4 |
| 3250 | OSCL | CONTSHIP OCEEAN STAR SERV. | | | SCAC3 |
| 3251 | OSCL | OVERSEAS LNG S2 CORPORATION | | | SCAC4 |
| 3252 | OSCM | ORION SHIPMANAGEMENT CO | | | SCAC4 |
| 3253 | OSCN | OCEAN STAR CONTAINER LINE | | | SCAC3 |
| 3254 | OSCN | OCEAN STAR CONTAINER LINES | | | SCAC4 |
| 3255 | OSCO | OSCO SHIPPING A/S | | | SCAC3 |
| 3256 | OSCO | ORTHOS SHIPPING CORPORATION | | | SCAC4 |
| 3257 | OSCP | OMEGA SHIPPING CO INC | | | SCAC4 |
| 3258 | OSCQ | OM SEAFOOD CO INC | | | SCAC4 |
| 3259 | OSCT | OLSON, STEVEN C TRUCKING | | | SCAC4 |
| 3260 | OSCU | OCI COMPANY LTD | | ROK | BIC |
| 3261 | OSCX | Oil Seeds Co. | 8/1920-7/1923 | | NAKINA |
| 3262 | OSCX | OIL SEEDS CO. | | | PWRC |
| 3263 | OSCZ | INTERMODAL SERVICES, INC. | | | PWRC |
| 3264 | OSCZ | Intermodal Services Inc. | | | RSRV |
| 3265 | OSCZ | INTERMODAL SERVICES, INC. | | | SCAC4 |
| 3266 | OSD | National Airborne Operations Center, U.S. Strategic Command | Callsign: Secdef, | USA | AVCODES |
| 3267 | OSDL | OVERSEAS DRILLING LIMITED | | | SCAC4 |
| 3268 | OSDT | OSTROM, DARREL TRUCKING LTD | | | SCAC4 |
| 3269 | OSDV | OMAXZ SA DE CV | | | SCAC4 |
| 3270 | OSE | Ostsächsische Eisenbahnfreunde e.V. | Löbau / Bautzen | D | privat-bahn.de |
| 3271 | OSE | | | GR | TRAFFIC |
| 3272 | OSE | Organismos Sidirodromon Ellados | | EL | VKM |
| 3273 | OSEC | OAKES & SONS ENTERPRIZE CO LLC | | | SCAC4 |
| 3274 | OSEE | ONE SIX EIGHT THREE ONE FOUR | | | SCAC4 |
| 3275 | OSEE | Ostseebus | | D | TRAFFIC |
| 3276 | OSEF | ONE SIX EIGHT SEVEN FIVE ONE | | | SCAC4 |
| 3277 | OSEF | Ostsächsische Eisenbahnfreunde e.V | | DE | VKM |
| 3278 | OSEK | Austrovapor Bahnnostalgie Veranstaltungs GmbH | | AT | VKM |
| 3279 | OSEP | OCEAN STATE EXPRESS INC | | | SCAC3 |
| 3280 | OSER | OSER LEASING COMPANY INC | | | SCAC3 |
| 3281 | OSER | OBSCURA SANCHEZ, EDUARDO ERIC | | | SCAC4 |
| 3282 | OSES | OHIO SOUTHERN EXPRESS INC | | | SCAC3 |
| 3283 | OSEY | OSPREY EQUIPMENT CORPORATION | | | SCAC4 |
| 3284 | OSFA | OLD SOUTH FREIGHT SERVICES INC | | | SCAC4 |
| 3285 | OSFB | ON THE SPOT FREIGHT | | | SCAC4 |
| 3286 | OSFC | OLSEN, FRED & CO. | | | SCAC3 |
| 3287 | OSFD | OHIO STATE FORWARDING INC | | | SCAC3 |
| 3288 | OSFI | OSCEOLA FOOD INC | | | SCAC3 |
| 3289 | OSFN | ONE SEVEN FIVE ZERO NINE SEVEN EIGH | | | SCAC4 |
| 3290 | OSFS | ON-SITE FUEL SERVICE INC | | | SCAC4 |
| 3291 | OSFW | ONE SIX FIVE ONE TWO SIX TWO (16512 | | | SCAC4 |
| 3292 | OSGA | OSG DELAWARE BAY LIGHTERING LLC | | | SCAC4 |
| 3293 | OSGB | OVERSEAS GALENA BAY LLC | | | SCAC4 |
| 3294 | OSGC | OSG CAR CARRIERS, INC. | | | SCAC3 |
| 3295 | OSGD | OSTERGARD TRUCKING | | | SCAC4 |
| 3296 | OSGE | OSAGE EXPRESS | | | SCAC3 |
| 3297 | OSGE | OLIVAS GRANADOS, JESUS MARIA | | | SCAC4 |
| 3298 | OSGF | OSG TWO FOUR TWO (242) LLC | | | SCAC4 |
| 3299 | OSGG | OSG COURAGEOUS LLC | | | SCAC4 |
| 3300 | OSGH | OSG TWO FOUR THREE (243) LLC | | | SCAC4 |
