| 5201 | MMA | MONTREAL, MAINE & ATLANTIC RAILWAY | | | PWRC |
| 5202 | MMA | Montreal, Maine and Atlantic Railway | | | RSRV |
| 5203 | MMA | MONTREAL MAINE AND ATLANTIC RAILWAY | | | SCAC4 |
| 5204 | MMA | Montreal, Maine & Atlantic Railway Company | | CDN | TRAFFIC |
| 5205 | MMAC | MONTREAL, MAINE & ATLANTIC RAILWAY | | | PWRC |
| 5206 | MMAC | Montreal, Maine and Atlantic Railway | | | RSRV |
| 5207 | MMAE | M & M TRANSPORTATION | | | SCAC4 |
| 5208 | MMAF | MSR MOBILE STAGE RENTALS LLC | | | SCAC4 |
| 5209 | MMAG | MCAULIFFE MARITIME AGENCY INC | | | SCAC4 |
| 5210 | MMAI | MJ PETROLEUM | | | SCAC4 |
| 5211 | MMAJ | MOSMATIC CORPORATION | | | SCAC4 |
| 5212 | MMAM | MILLENIUM MARINE | | | SCAC4 |
| 5213 | MMAP | M & M TRANSPORT INC | | | SCAC4 |
| 5214 | MMAU | MAERSK A/S | | DK | BIC |
| 5215 | MMAU | AP MOLLER | | | SCAC4 |
| 5216 | MMAV | MORALES MOVING & STORAGE CO INC | | | SCAC4 |
| 5217 | MMAW | MOOMAW | | | SCAC4 |
| 5218 | MMAX | Martin Marietta Materials, Inc. | added 7/2007 | | NAKINA |
| 5219 | MMAX | Martin Marietta Corp. | added 4/1985; 1/1994; eliminated 7/1997; 7/2000-7/2005 (not listed) | | NAKINA |
| 5220 | MMAX | Martin Marietta Aluminum Inc. | added 7/1982; eliminated 1/1985 | | NAKINA |
| 5221 | MMAX | Defense Plant Corp. | 1/1945-1/1946 | | NAKINA |
| 5222 | MMAX | Martin Marietta Aluminum Inc. | added 7/82; eliminated 1/85 | | NRHS |
| 5223 | MMAX | Martin Marietta Corp. | added 4/85; 1/94; eliminated 7/97; 7/2000 | | NRHS |
| 5224 | MMAX | *DEFENSE PLANT CORP. | | | PWRC |
| 5225 | MMAX | +MARTIN MARIETTA MATERIALS, INC. [MARTIN MARIETTA ALUMINUM, INC.] | | | PWRC |
| 5226 | MMAX | Martin Marietta Aluminum | | | RSRV |
| 5227 | MMAX | MARTIN MARIETTA MATERIALS INC | | | SCAC4 |
| 5228 | MMAZ | MARTIN MARIETTA AGREGATES, INC. | | | PWRC |
| 5229 | MMBA | MI MAMAS TORTILLAS | | | SCAC4 |
| 5230 | MMBC | M & M TRUCKING | | | SCAC4 |
| 5231 | MMBE | MARK, MARTIN TRUCKING | | | SCAC4 |
| 5232 | MMBJ | MOTORGRAPHIC | | | SCAC4 |
| 5233 | MMBK | MMC TRANSPORT INC | | | SCAC4 |
| 5234 | MMBL | MANUFACTURE DE MEUBLES VALENTINO IN | | | SCAC4 |
| 5235 | MMBL | Montebello Municipal Bus Lines | | US-CA | TRAFFIC |
| 5236 | MMBM | M & M TRUCKING | | | SCAC4 |
| 5237 | MMBP | MORSE MOVING AND STORAGE INDIANAPOL | | | SCAC4 |
| 5238 | MMBQ | MINTON MOTOR TRANSPORT INC | | | SCAC4 |
| 5239 | MMBX | Master Builders, Inc. | added 10/1987; 1/1994; eliminated 10/1995; added 10/1996; eliminated 1/1997; 7/2000-7/2005 (not listed) | | NAKINA |
| 5240 | MMBX | Martin Marietta Corp. | added 1/1979; 1/1980; eliminated 7/1986 | | NAKINA |
| 5241 | MMBX | Martin Marietta Corp. | added 1/79; 1/80; eliminated 7/86 | | NRHS |
| 5242 | MMBX | Master Builders, Inc. | added 10/87; 1/94; eliminated 10/95; added 10/96; eliminated 1/97; 7/2000 | | NRHS |
| 5243 | MMBX | MARTIN MARIETTA CORPORATION [MASTER BUILDERS, INC.] | | | PWRC |
| 5244 | MMBX | Martin Marietta Corporation (Master Builders) | | | RSRV |
| 5245 | MMBX | MASTER BUILDERS, INC. | | | SCAC4 |
| 5246 | MMC | Aermarche | Callsign: Aermarche, | I | AVCODES |
| 5247 | MMC | Aermarche | | | ICAO1 |
| 5248 | MMCA | M&M CARTAGE, INC | | | SCAC1 |
| 5249 | MMCA | M & M CARTAGE INC | | | SCAC4 |
| 5250 | MMCB | M & M WESTCOAST PRODUCE INC | | | SCAC4 |
| 5251 | MMCE | MAMM | | | SCAC4 |
| 5252 | MMCG | M & M CARTAGE COMPANY INC | | | SCAC4 |
| 5253 | MMCH | MILITARY MOVERS LLC | | | SCAC4 |
| 5254 | MMCI | MISENER MARINE CONSTRUCTION INCORPO | | | SCAC4 |
| 5255 | MMCK | M & M TRUCKING LLC | | | SCAC4 |
| 5256 | MMCS | MCL MCGILL CARRIERS LTD | | | SCAC4 |
| 5257 | MMCT | MERCER MORTON COOP TRANSPORT ASSN | | | SCAC4 |
| 5258 | MMCU | CMA-CGM | | F | BIC |
| 5259 | MMCU | CIE DES MESSAGERIES MARITIMES | | | PWRC |
| 5260 | MMCU | CIE Des Messageries Maritimes | | | RSRV |
| 5261 | MMCU | CMA-CGM | | | SCAC4 |
| 5262 | MMCV | MOUNTAINM | | | SCAC4 |
| 5263 | MMCW | MAMM | | | SCAC4 |
| 5264 | MMCX | Pan American Railway Co. | added 4/2002; 7/2005 | | NAKINA |
| 5265 | MMCX | TransMatrix, Inc. | added 7/1989; 1/1994-7/2000; eliminated 4/2002 | | NAKINA |
| 5266 | MMCX | M & M Chemical Products, Inc. | added 7/1977; 1/1980; eliminated 7/1989 | | NAKINA |
| 5267 | MMCX | North American Car Corp. | added 1/1961; 4/1961-4/1970; eliminated 1/1972 | | NAKINA |
| 5268 | MMCX | McClintle-Marshall Construction Co. | 7/1923 | | NAKINA |
| 5269 | MMCX | M & M Chemical Products, Inc. | added 7/77; 1/80; eliminated 7/89 | | NRHS |
| 5270 | MMCX | North American Car Corp. | 4/61-4/70; eliminated 1/72 | | NRHS |
| 5271 | MMCX | TransMatrix, Inc. | added 7/89; 1/94-7/2000 | | NRHS |
| 5272 | MMCX | *MCCLINTLE-MARSHALL CONSTRUCTION CO. | | | PWRC |
| 5273 | MMCX | *NORTH AMERICAN CAR CORP. | | | PWRC |
| 5274 | MMCX | +PAN AMERICAN RAILWAY CO. [(TMIX) TRANSMATRIX, INC.; M & M CHEMICAL PRODUCTS INC.] | | | PWRC |
| 5275 | MMCX | M&M Chemical Products (TransMatrix) | | | RSRV |
| 5276 | MMCX | PAN AMERICAN RAILWAY COMPANY | | | SCAC4 |
| 5277 | MMCX | TransMatrix, Inc. | | USA | TRAFFIC |
| 5278 | MMCY | M & M DELIVERY INC | | | SCAC4 |
| 5279 | MMCZ | M & M CORPORATION | | | PWRC |
| 5280 | MMD | Air Alsie A/S | Callsign: Mermaid, ICAO designator changed from ALS | DK | AVCODES |
| 5281 | MMD | Alsie Express | IATA: 6I, Callsign: Mermaid, Operated by Air Alsie | DK | AVCODES |
| 5282 | MMD | Air Alsie | | | ICAO1 |
| 5283 | MMDA | M M & M TRANSPORTATION LLC | | | SCAC4 |
| 5284 | MMDB | MID MOVING & STORAGE INC | | | SCAC4 |
| 5285 | MMDC | M & M DELIVERIES INC | | | SCAC4 |
| 5286 | MMDD | MERCHANTS MOVING & STORAGE INC | | | SCAC4 |
| 5287 | MMDE | MULTI FREIGHT EXPRESS INC | | | SCAC4 |
| 5288 | MMDF | MONTRIG FREIGHT | | | SCAC4 |
| 5289 | MMDG | MMD LOGISTICS INC | | | SCAC4 |
| 5290 | MMDK | MODUS MEDICAL DEVICES INC | | | SCAC4 |
| 5291 | MMDN | MULTI-MODAL TRUCKING INC | | | SCAC4 |
| 5292 | MMDR | M & M DELIVERY LLC | | | SCAC4 |
| 5293 | MMDT | MULTIMODAL TRANSPORTATION CORP INC | | | SCAC1 |
| 5294 | MME | Multimedia Entertainment Group Air (Pty) Ltd t/a Mega | Callsign: Majestic Air, | ZA | AVCODES |
| 5295 | MME | Märkische Museums - Eisenbahn e.V. | Plettenberg | D | privat-bahn.de |
| 5296 | MMEA | MISSM | | | SCAC4 |
| 5297 | MMED | MOBILITY MEDICAL | | | SCAC4 |
| 5298 | MMEF | MULTI MODE LOGISTICS LLC | | | SCAC4 |
| 5299 | MMEG | MID-MICHIGA | | | SCAC4 |
| 5300 | MMEH | M M TRUCKING | | | SCAC4 |
