| 6301 | MOHX | Monsanto Co. | added 7/64; 7/65-1/94; eliminated 1/98 | | NRHS |
| 6302 | MOHX | Solutia Inc. | added 1/98; 7/2000 | | NRHS |
| 6303 | MOHX | SOLUTIA INCORPORATED [(MONX) MONSANTO COMPANY] | | | PWRC |
| 6304 | MOHX | Monsanto | | | RSRV |
| 6305 | MOHX | SOLUTIA INC | | | SCAC4 |
| 6306 | MOIB | MAC CONTAINER LINE | | | SCAC4 |
| 6307 | MOIC | MOEN INCORPORATED | | | SCAC4 |
| 6308 | MOIE | MONTICELLI | | | SCAC4 |
| 6309 | MOII | MCNEILL OIL CO INC | | | SCAC4 |
| 6310 | MOIL | MCPHERSON OIL COMPANY INC | | | SCAC4 |
| 6311 | MOIN | MORRIS VAN LINES INC | | | SCAC4 |
| 6312 | MOIQ | MORRELL OVERSIZE INC | | | SCAC4 |
| 6313 | MOIS | MAMNASS LOGISTICS | | | SCAC4 |
| 6314 | MOIT | MORRIS OIL TRANSPORTERS LLC | | | SCAC4 |
| 6315 | MOIY | MONSON OIL COMPANY | | | SCAC4 |
| 6316 | MOJA | MOJAVE TRANSPORTATION CO | | | SCAC1 |
| 6317 | MOJE | MOORE, JAMES EUNICE | | | SCAC4 |
| 6318 | MOJN | MORIN, JEAN INC | | | SCAC4 |
| 6319 | MOJU | MONTEIRO CONSTRUCOES E SERVICOS LTDA | | BR | BIC |
| 6320 | MOJU | MONTEIRO CONSTRUCOES E SERVICOS LTD | | | SCAC4 |
| 6321 | MOK | Light Aircraft Association of The Czech Republic | | CZ | AVCODES |
| 6322 | MOKC | MOORE TRUCKING LLC | | | SCAC4 |
| 6323 | MOKD | M-OK DISTRIBUTION INC | | | SCAC4 |
| 6324 | MOKG | MOLINE TRUCKING | | | SCAC4 |
| 6325 | MOKH | MORALES, O TRUCKING | | | SCAC4 |
| 6326 | MOKM | MOREHOUS | | | SCAC4 |
| 6327 | MOKN | MO-KAN DISTRIBUTION SERVICE, INC | | | SCAC1 |
| 6328 | MOKR | MORKS SERVICE INC | | | SCAC4 |
| 6329 | MOKS | MONKEYS TRANSPORT INC | | | SCAC4 |
| 6330 | MOL | Shah Air | Callsign: Bagdan, | KZ | AVCODES |
| 6331 | MOL | MOUNTAIN LINE | | | SCAC4 |
| 6332 | MOL | MOL Hungarian Oil and Gas Company | | HU | VKM |
| 6333 | MOLA | MACRO INCORPORATED | | | SCAC4 |
| 6334 | MOLC | MIDLAND TRANSPORTS | | | SCAC4 |
| 6335 | MOLCY | MOL CY NV | | BE | VKM |
| 6336 | MOLE | MOONLIGHTER EXPRESS | | | SCAC4 |
| 6337 | MOLH | MOL CONSOLIDATION SERVICE LIMITED | | | SCAC4 |
| 6338 | MOLI | MONT CAL LOGISTICS INC | | | SCAC4 |
| 6339 | MOLI | Molinari Rail Deutschland GmbH | | DE | VKM |
| 6340 | MOLJ | MOLINELLI, JOHN INC | | | SCAC4 |
| 6341 | MOLK | MORRELL & MORRELL LP | | | SCAC4 |
| 6342 | Molli | Mecklenburgische Bäderbahn Molli GmbH & Co | Bad Doberan | D | privat-bahn.de |
| 6343 | MOLLI | Mecklenburgische Bäderbahn Molli | | D | TRAFFIC |
| 6344 | MOLM | MORALES OLMOS, MANUEL | | | SCAC4 |
| 6345 | MOLS | M O L TRANSPORT | | | SCAC4 |
| 6346 | MOLU | MITSUI O.S.K. LINES LTD | | J | BIC |
| 6347 | MOLU | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6348 | MOLU | Mitsui O.S.K. Lines | | | RSRV |
| 6349 | MOLU | MITSUI O.S.K. LINES | | | SCAC1 |
| 6350 | MOLU | MITSUI O S K LINES LTD | | | SCAC4 |
| 6351 | MOLV | MORAN OLVERA, EDGAR GILBERTO | | | SCAC4 |
| 6352 | MOLX | International Molasses Corp. Ltd. | added 1/1998; eliminated 4/1998; 7/2000-7/2005 (not listed) | | NAKINA |
| 6353 | MOLX | Emmel Corp. | added 10/1958; eliminated 10/1959 | | NAKINA |
| 6354 | MOLX | Emmel Co. | added 7/1958; eliminated 10/1958 | | NAKINA |
| 6355 | MOLX | McCombs Producing & Refining Co. | 8/1920 | | NAKINA |
| 6356 | MOLX | Emmel Co. | added 7/58; eliminated 10/58 | | NRHS |
| 6357 | MOLX | Emmel Corp. | added 10/58; eliminated 10/59 | | NRHS |
| 6358 | MOLX | International Molasses Corp. Ltd. | added 1/98; eliminated 4/98; 7/2000 | | NRHS |
| 6359 | MOLX | *MCCOMBS PRODUCING & REFINING CO. | | | PWRC |
| 6360 | MOLX | *EMMEL CORP. | | | PWRC |
| 6361 | MOLX | +INTERNATIONAL MOLASSES CORP. LTD. | | | PWRC |
| 6362 | MOLX | International Molasses Corporation | | | RSRV |
| 6363 | MOLY | MOLES, WAYNE TRUCKING COMPANY | | | SCAC4 |
| 6364 | MOLZ | MOLASSES INDUSTRY | | | PWRC |
| 6365 | MOM | Modern Air GmbH & Co. KG. | Callsign: Modern Air, | D | AVCODES |
| 6366 | MOMA | MORRIS MARKETING CO INC | | | SCAC4 |
| 6367 | MOMC | MAIL-O-MATIC SERVICES LTD | | | SCAC4 |
| 6368 | MOMK | MOLINA & MEDINA TRUCKING INC | | | SCAC4 |
| 6369 | MOMM | MOOMAW MARKETING INC | | | SCAC4 |
| 6370 | MOMN | MONUME | | | SCAC4 |
| 6371 | MOMP | MOSELEY, GORDEN PETER | | | SCAC4 |
| 6372 | MOMU | HAPAG LLOYD A.G | | D | BIC |
| 6373 | MOMU | MONTEMAR S A | | | SCAC1 |
| 6374 | MOMU | MONTEMAR SA | | | SCAC4 |
| 6375 | MOMZ | MONTEREY MINE | | | PWRC |
| 6376 | MON | Monarch Airlines Ltd. | IATA: ZB, Callsign: Monarch, IATA Prefix: 974, AOC withdrawn by CAA 02 October 2017. | GB | AVCODES |
| 6377 | MON | Monarch Airlines Ltd. | IATA: OM, Callsign: Monarch, IATA designator changed to ZB | GB | AVCODES |
| 6378 | MON | Monarch Airlines | IATA: ZB | | ICAO1 |
| 6379 | MON | CSX Transportation, Inc. | added 7/1987; 1/1994-7/2005 | | NAKINA |
| 6380 | MON | Seaboard System R.R., Inc. | added 1/1983; eliminated 7/1987 | | NAKINA |
| 6381 | MON | Louisville and Nashville R.R. Co. | 1/1975-1/1980; eliminated 1/1983 | | NAKINA |
| 6382 | MON | Monon R.R. | 10/1957-10/1966 | | NAKINA |
| 6383 | MON | Monon R.R. | 10/57-10/66 | | NRHS |
| 6384 | MON | Louisville and Nashville R.R. Co. | 1/75-1/80; eliminated 1/83 | | NRHS |
| 6385 | MON | Seaboard System R.R., Inc. | added 1/83; eliminated 7/87 | | NRHS |
| 6386 | MON | CSX Transportation, Inc. | added 7/87; 1/94-7/2000 | | NRHS |
| 6387 | MON | CSX TRANSPORTATION, INC. [SEABOARD; MONON RAILROAD; LOUISVILLE & NASHVILLE RAILROAD CO.,; CHICAGO, INDIANAPOLIS & LOUISVILLE RR ] | | | PWRC |
| 6388 | MON | Monon Railroad (CSX Transportation) | | | RSRV |
| 6389 | MON | Chicago Indianapolis & Louisville Railroad (Monon) | Real: CIL | USA | TRAFFIC |
| 6390 | MONA | MORRISON TRUCKING | | | SCAC4 |
| 6391 | MONACELLI | Ditta Monicelli | | I | TRAFFIC |
| 6392 | MONB | MARDON STABLES | | | SCAC4 |
| 6393 | MONBS | Monroe Bus Service | | USA | TRAFFIC |
| 6394 | MONC | MONROE TRANSPORTATION SERVICES | | | SCAC1 |
| 6395 | MONC | MONROE TRANSPORTATION SERVICES INCO | | | SCAC4 |
| 6396 | MOND | MONSON, R E INC | | | SCAC4 |
| 6397 | MONDI | Mondi Stamboliiski | | BG | VKM |
| 6398 | MONF | MONFER S.p.A. | | IT | VKM |
| 6399 | MONJ | MONSE | | | SCAC4 |
| 6400 | MONK | MONKEYS TRUCKING INC | | | SCAC4 |
