| 4201 | AEPO | A E EXPRESS | | | SCAC3 |
| 4202 | AEPQ | AEP INDUSTRIES INC | | | SCAC3 |
| 4203 | AEPR | ALTI EXPRESS | | | SCAC4 |
| 4204 | AEPS | AMERICAN ELECTRIC POWER SERVICE CORPORATION | | | PWRC |
| 4205 | AEPT | ADEPT TRANSPORT INC | | | SCAC3 |
| 4206 | AEPT | ARCTIC EQUIPMENT MANUFACTURING CORP | | | SCAC4 |
| 4207 | AEPU | AMERICAN LINES INC. | | | PWRC |
| 4208 | AEPU | American Lines | | | RSRV |
| 4209 | AEPU | AMERICAN LINES | | | SCAC3 |
| 4210 | AEPU | AMERICAN LINES | | | SCAC4 |
| 4211 | AEPV | ALLIED EXPRESS | | | SCAC3 |
| 4212 | AEPW | AEP TRANSPORTATION INC | | | SCAC4 |
| 4213 | AEPX | American Electric Power Service Corp. | added 4/1975; 1/1980-7/2005 | | NAKINA |
| 4214 | AEPX | American Electric Power Service Corp. (cars being restencilled from APWX) | 1/1975 | | NAKINA |
| 4215 | AEPX | Appalachian Power Co. | added 10/1958; 4/1961-4/1970; eliminated 4/1975 | | NAKINA |
| 4216 | AEPX | Appalachian Electric Power Co. | 1/1943-10/1957; eliminated 10/1958 | | NAKINA |
| 4217 | AEPX | Appalachian Electric Power Co. | 1/52-10/57; eliminated 10/58 | | NRHS |
| 4218 | AEPX | Appalachian Power Co. | added 10/58; 4/61-4/70; eliminated 4/75 | | NRHS |
| 4219 | AEPX | American Electric Power Service Corp. (cars being restencilled from APWX) | Jan-75 | | NRHS |
| 4220 | AEPX | American Electric Power Service Corp. | added 4/75; 1/80-7/2000 | | NRHS |
| 4221 | AEPX | AMERICAN ELECTRIC POWER SERVICE CORPORATION [APPALACHIAN POWER] | | | PWRC |
| 4222 | AEPX | American Electric Power Service Corporation | | | RSRV |
| 4223 | AEPZ | AEP COAL TERMINAL | | | PWRC |
| 4224 | AEQ | AviaExpressCruise Airlines | IATA: E6, Designator E6 reinstated by IATA | RUS | AVCODES |
| 4225 | AEQ | Air Express in Sweden AB | Callsign: Lunia, | S | AVCODES |
| 4226 | AEQ | Air Express | | | ICAO1 |
| 4227 | AEQC | ABILENE EQUIPMENT INC | | | SCAC3 |
| 4228 | AEQC | ABILENE MOTOR EXPRESS INC | | | SCAC4 |
| 4229 | AEQG | AE LOGISTICS INC | | | SCAC4 |
| 4230 | AEQI | ADVANTAGE EQUIPMENT EXPRESS AND DIS | | | SCAC4 |
| 4231 | AEQK | ACE TRUCKING INC | | | SCAC3 |
| 4232 | AEQL | ACCESS RELOCATION | | | SCAC4 |
| 4233 | AEQR | ACADEMY EQUIPMENT RENTALS | | | SCAC3 |
| 4234 | AEQR | ACADEMY EQUIPMENT RENTALS | | | SCAC4 |
| 4235 | AEQV | ALLEN, G EQUIPMENT CORPORATION | | | SCAC4 |
| 4236 | AEQX | Atel Equipment Corp. | 7/2005 (not listed); added 10/2005 | | NAKINA |
| 4237 | AEQX | ATEL EQUIPMENT CORP. | | | PWRC |
| 4238 | AEQX | ATEL EQUIPMENT CORPORATION | | | SCAC4 |
| 4239 | AER | Alaska Central Express, Inc. | IATA: KO, Callsign: Ace Air, | USA | AVCODES |
| 4240 | AER | Ace Air Cargo Express | Callsign: Ace Air, | USA | AVCODES |
| 4241 | AER | Alaska Central Express | IATA: KO | | ICAO1 |
| 4242 | AER | Algoma Eastern Ry. (Canadian Pacific Ry.) | 7/1932-4/1938 | | NAKINA |
| 4243 | AER | Algoma Eastern Ry. | 7/1930 | | NAKINA |
| 4244 | AER | Algoma Eastern Ry. | Apr-38 | | NRHS |
| 4245 | AER | CANADIAN PACIFIC RY. [ALGOMA EASTERN RAILWAY] | | | PWRC |
| 4246 | AER | Algoma Eastern Railway | | | RSRV |
| 4247 | AER | ANNETT BUS LINES | | | SCAC4 |
| 4248 | AERA | AERO TRANSPORTATION INC | | | SCAC4 |
| 4249 | AERC | Albany & Eastern R.R. Co. | added 10/1999; 7/2000-7/2005 | | NAKINA |
| 4250 | AERC | Albany & Eastern R.R. Co. | added 10/99; 7/2000 | | NRHS |
| 4251 | AERC | ALBANY & EASTERN RAILROAD | | | PWRC |
| 4252 | AERC | Albany and Eastern Railroad | | | RSRV |
| 4253 | AERC | ALBANY & EASTERN RAILROAD COMPANY | | | SCAC4 |
| 4254 | AERC | Albany and Eastern Railroad | | USA | TRAFFIC |
| 4255 | AERE | AMER-TRAN INC | | | SCAC3 |
| 4256 | AERF | AEROTEC ENGINES LTD | | | SCAC4 |
| 4257 | AERG | AERONET INC | | | SCAC4 |
| 4258 | AERI | AERO INDUSTRIES INC | | | SCAC3 |
| 4259 | AERI | AIRPORT EQUIPMENT RENTALS INC | | | SCAC4 |
| 4260 | AERJ | AUTO EXPRESS ROJA SA DE CV | | | SCAC4 |
| 4261 | AERL | AERO ENERGY | | | SCAC4 |
| 4262 | AERM | AERO MAYFLOWER TRANSIT COMPANY, INC. | | | SCAC3 |
| 4263 | AERM | AERO MAYFLOWER TRANSIT COMPANY INC | | | SCAC4 |
| 4264 | AERN | AERO-TRANSIT INC | | | SCAC3 |
| 4265 | AERN | AERONET WORLDWIDE | | | SCAC4 |
| 4266 | AERO | AERO TRUCKING INC | | | SCAC3 |
| 4267 | AERO | Aero Vodochody | | CS | TRAFFIC |
| 4268 | AERP | AEROWPRES CORPORATION | | | SCAC3 |
| 4269 | AERP | ARCHERS POULTRY FARM LTD | | | SCAC4 |
| 4270 | AERR | ACME FREIGHT SERVICES CORP | | | SCAC4 |
| 4271 | AERS | AERS Rail Services Deutchland GmbH | | DE | VKM |
| 4272 | AERT | AGTRON ENTERPRISES INC | | | SCAC4 |
| 4273 | AERU | AEROSOLEX LLC | | RUS | BIC |
| 4274 | AERV | A & E RELOCATION SERVICES | | | SCAC4 |
| 4275 | AERX | Ameren Energy Resources Generating Co. | 7/2005 (not listed) | | NAKINA |
| 4276 | AERX | AMEREN ENERGY RESOURCES GENERATING CO. | | | PWRC |
| 4277 | AERX | AMEREN ENERGY RESOURCES GENERATING | | | SCAC4 |
| 4278 | AERY | ALL SERVICE DELIVERY, INC | | | SCAC3 |
| 4279 | AERY | ALL SERVICE DELIVERY INC | | | SCAC4 |
| 4280 | AES | Aerolineas Centrales de Colombia S.A. (ACES) | IATA: VX, Callsign: ACES, IATA Prefix: 137, Ceased operations on 20 August 2003. | CO | AVCODES |
| 4281 | AES | Aerosur Paraguay S.A. | IATA: PQ, Callsign: Aeroparaguay, IATA Prefix: 682, Ceased operations on 01 July 2012. Name changed from Aero Regional Paraguaya S.A. | PY | AVCODES |
| 4282 | AES | Aerospace Engineering Services | Callsign: Gemina, | M | AVCODES |
| 4283 | AES | ACES Colombia | IATA: VX | | ICAO1 |
| 4284 | AES | ALAMO SHUTTLE SERVICE | | | SCAC4 |
| 4285 | AES | Aerolineas Centrales de Colombia S.A. (ACES) | | CO | TRAFFIC |
| 4286 | AESA | AESA, INC. | | | SCAC3 |
| 4287 | AESA | ACOSTA ESTRADA, SERGIO HUGO | | | SCAC4 |
| 4288 | AESB | A E S TRANSPORTATION INC | | | SCAC3 |
| 4289 | AESC | ANYTIME EXPEDITE SERVICE LLC | | | SCAC4 |
| 4290 | AESD | AMLIN EXPEDITE SERVICE LTD | | | SCAC3 |
| 4291 | AESE | ABO ENVIRONMENTAL SERVICES | | | SCAC4 |
| 4292 | AESF | AUTO EXPRESS SAN FRANCISCO | | | SCAC4 |
| 4293 | AESG | AMERICAN SIGHTSEEING (DIV OF LOWCOU | | | SCAC3 |
| 4294 | AESI | AERO AIR FREIGHT DELIVERY INC | | | SCAC3 |
| 4295 | AESJ | ACCESS TRANSPORTATION | | | SCAC3 |
| 4296 | AESJ | ALPHA EXPRESS SERVICES CORP | | | SCAC4 |
| 4297 | AESL | AUTO EXPRESS SALDIVAR | | | SCAC4 |
| 4298 | AESO | ASTERION ENTERPRISES SA | | | SCAC4 |
| 4299 | AESP | AESOPH, GARY | | | SCAC3 |
| 4300 | AESQ | ATLANTTRAFIK EXPRESS SERVICE | | | SCAC3 |
