| 5101 | MLSX | Monsanto Co. | added 10/97; added 1/98; 7/2000 | | NRHS |
| 5102 | MLSX | MONSANTO COMPANY | | | PWRC |
| 5103 | MLSX | Monsanto | | | RSRV |
| 5104 | MLSX | MONSANTO COMPANY | | | SCAC4 |
| 5105 | MLT | Moldtransavia | Callsign: Moldtransavia, | MD | AVCODES |
| 5106 | MLT | Maritalia | Callsign: Marital, | SN | AVCODES |
| 5107 | MLT | Hangar 8 AOC Malta Limited t/a Maleth-Aero | Callsign: Maleth, Name changed to Maleth-Aero AOC Ltd. | M | AVCODES |
| 5108 | MLT | Maleth-Aero AOC Ltd | Callsign: Maleth, Name changed from Hangar 8 AOC Malta Limited t/a Maleth-Aero | M | AVCODES |
| 5109 | MLT | Maleth-Aero AOC Ltd | IATA: DB, Callsign: Maleth, IATA Prefix: 094, Name changed from Hangar 8 AOC Malta Limited t/a Maleth-Aero | M | AVCODES |
| 5110 | MLT | Malmöhus Länstrafik | | S | TRAFFIC |
| 5111 | MLTA | MILLS TRANSPORTATION INC | | | SCAC4 |
| 5112 | MLTC | MALONE TRANSPORT INC | | | SCAC4 |
| 5113 | MLTD | MERCURY LAUNCH & TUG LTD | | | SCAC4 |
| 5114 | MLTE | MELTON LOGISTICS LLC | | | SCAC4 |
| 5115 | MLTH | MALLOY, T H & SONS INC | | | SCAC4 |
| 5116 | MLTI | M & L TRANSPORT INC | | | SCAC4 |
| 5117 | MLTJ | M & L TRUCKING INC | | | SCAC4 |
| 5118 | MLTM | MULTIMODAL | | | SCAC4 |
| 5119 | MLTN | MELTON, J TRUCKING CO INC | | | SCAC4 |
| 5120 | MLTO | MALTAIS TRANSPORT ENR | | | SCAC4 |
| 5121 | MLTR | M L T TRANSPORTATION | | | SCAC4 |
| 5122 | MLTU | MULCON SA | | ROU | BIC |
| 5123 | MLTU | CP RAIL INTERMODAL FREIGHT SERVICES | | | SCAC3 |
| 5124 | MLTU | CP RAIL INTERMODAL FREIGHT SERVICES | | | SCAC4 |
| 5125 | MLTX | Maple Leaf Tank Car Co. | 7/1935; 7/1937 (not listed) | | NAKINA |
| 5126 | MLTX | MAPLE LEAF TANK CAR CO. | | | PWRC |
| 5127 | MLTY | MLT TRANSPORTATION LLC | | | SCAC4 |
| 5128 | MLU | Zracno Pristaniste Mali Losinj | | | ICAO1 |
| 5129 | MLUG | McCULLOUGH, WILLIAM G | | | SCAC1 |
| 5130 | MLUG | MCCULLOUGH, WM G CO | | | SCAC4 |
| 5131 | MLUL | MOL LOGISTICS USA INC | | | SCAC4 |
| 5132 | MLUM | MCCALLUM TRANSFER INC | | | SCAC4 |
| 5133 | MLUS | MORENO ROLDAN, LUIS | | | SCAC4 |
| 5134 | MLUT | MALOU THERESA K/S | | | SCAC4 |
| 5135 | MLUX | Solutia Inc. | added 1/1998; 7/2000-7/2005; eliminated 7/2009 | | NAKINA |
| 5136 | MLUX | Monsanto Co. | added 7/1964; 7/1965-1/1994; eliminated 1/1998 | | NAKINA |
| 5137 | MLUX | Monsanto Chemical Co. | added 7/1959; 4/1961; eliminated 7/1964 | | NAKINA |
| 5138 | MLUX | Monsanto Chemical Co. | added 7/59; 4/61; eliminated 7/64 | | NRHS |
| 5139 | MLUX | Monsanto Co. | added 7/64; 7/65-1/94; eliminated 1/98 | | NRHS |
| 5140 | MLUX | Solutia Inc. | added 1/98; 7/2000 | | NRHS |
| 5141 | MLUX | SOLUTIA INCORPORATED [(MONX) MONSANTO COMPANY] | | | PWRC |
| 5142 | MLUX | Solutia | | | RSRV |
| 5143 | MLUX | SOLUTIA INC | | | SCAC4 |
| 5144 | MLV | Air Moldova International, S.A. | IATA: RM, Callsign: Moldova International, IATA Prefix: 283, Designator RM recalled by IATA | MD | AVCODES |
| 5145 | MLV | Air Moldova International, S.A. | IATA: 3R, IATA designator changed to RM | MD | AVCODES |
| 5146 | MLV | Martinsberger Lokalbahnverein | | AT | VKM |
| 5147 | MLVG | MULTIVIAS LOGISTICAS SA DE CV | | | SCAC4 |
| 5148 | MLVK | MILLER, L W LIVESTOCK INC | | | SCAC4 |
| 5149 | MLVP | MESTON LIVESTOCK TRANSPORT LTD | | | SCAC4 |
| 5150 | MLVQ | MELVIN TRANSPORT INC | | | SCAC4 |
| 5151 | MLVT | MCILVAINE TRUCKING INC | | | SCAC4 |
| 5152 | MLWA | MALWA CARTAGE INC | | | SCAC4 |
| 5153 | MLWQ | M C LASER WERKS INC | | | SCAC4 |
| 5154 | MLWS | MILLER, LEWIS H | | | SCAC4 |
| 5155 | MLWX | MLWX Co. | 1/1945-10/1957; eliminated 7/1960 | | NAKINA |
| 5156 | MLWX | MLWX Co. | 1/52-10/57; eliminated 7/60 | | NRHS |
| 5157 | MLWX | MLWX CO. | | | PWRC |
| 5158 | MLWY | MILKY WAY TRANSPORT CO INC | | | SCAC4 |
| 5159 | MLX | Malawi Express Limited | Callsign: Malawi Express, | MW | AVCODES |
| 5160 | MLX | Malawi Express | | | ICAO1 |
| 5161 | MLX | Master Lubricants Co. | 4/1938-4/1961; eliminated 7/1963 | | NAKINA |
| 5162 | MLX | Master Lubricants Co. | 4/38-4/61; eliminated 7/63 | | NRHS |
| 5163 | MLX | MASTER LUBRICANTS CO. | | | PWRC |
| 5164 | MLXB | M & L TRANSPORT OF PA LLC | | | SCAC4 |
| 5165 | MLXC | MALLARD EXPRESS LLC | | | SCAC4 |
| 5166 | MLXE | MILAN EXPRESS CO INC (TRUCKLOAD DIV | | | SCAC4 |
| 5167 | MLXH | MELLENIA TRANSPORT | | | SCAC4 |
| 5168 | MLXI | MCLX INC | | | SCAC4 |
| 5169 | MLXJ | MILLER, J EXPRESS INC | | | SCAC4 |
| 5170 | MLXK | MANILA EXPRESS LOGISTICS INC | | | SCAC4 |
| 5171 | MLXL | METAL TRANSPORT LLC | | | SCAC4 |
| 5172 | MLXM | MILLER TRANSPORTATION | | | SCAC4 |
| 5173 | MLXN | MILES TRANSPORTATION LLC | | | SCAC4 |
| 5174 | MLXO | MCLEOD EXPRESS LLC | | | SCAC4 |
| 5175 | MLXP | MILAN EXPRESS CO | | | SCAC1 |
| 5176 | MLXP | MILAN EXPRESS CO INC | | | SCAC4 |
| 5177 | MLXQ | MILLER TRANSPORT | | | SCAC4 |
| 5178 | MLXS | M & L EXPRESSWAY INC | | | SCAC4 |
| 5179 | MLXT | MULLINAX TRANSPORT COMPANY INC | | | SCAC4 |
| 5180 | MLXV | MILLS, R E TRANSPORTATION SERVICES | | | SCAC4 |
| 5181 | MLYH | MAINE-LY HEATING OIL | | | SCAC4 |
| 5182 | MLYK | MITCHELL, LARRY TRUCKING INC | | | SCAC4 |
| 5183 | MLYL | MARTELLY, LANCE | | | SCAC4 |
| 5184 | MLYT | MALONEY TRUCKING | | | SCAC4 |
| 5185 | MLZ | Magadanavialising, Joint-Stock Company | Callsign: Maglease, | RUS | AVCODES |
| 5186 | MLZ | Meteologic Pty Ltd | | AUS | AVCODES |
| 5187 | MLZ | MONTANA LIMESTONE | | | PWRC |
| 5188 | MLZF | MELZERS FUEL SERVICE INC | | | SCAC4 |
| 5189 | MLZR | MINEGAR LASER SCREED RENTALS INC | | | SCAC4 |
| 5190 | MM | Sociedad Aeronautica de Medellin Consolidada S.A. (SAM) | ICAO: SAM, Callsign: Sam, IATA Prefix: 334, Ceased operations in October 2010. Designator MM reinstated by IATA | CO | AVCODES |
| 5191 | MM | EuroAtlantic Airways, S.A. | ICAO: MMZ, Callsign: Euroatlantic, IATA Prefix: 551, IATA designator changed to YU. Formerly Air Zarco d/b/a Air Maderia | P | AVCODES |
| 5192 | MM | Air Madeira, S.A. | ICAO: MMZ, Name changed to Air Zarco | P | AVCODES |
| 5193 | MM | Air Zarco t/a Air Maderia | ICAO: MMZ, Callsign: Zarco, Formerly Air Madeira S.A. Name changed to EuroAtlantic Airways � Transportes A�reos S.A. | P | AVCODES |
| 5194 | MM | Peach Aviation Limited | ICAO: APJ, Callsign: Air Peach, | J | AVCODES |
| 5195 | MM | Malta Air Travel Ltd d/b/a Malta MedAir | ICAO: MMO, Callsign: Malit, IATA designator changed to MT. | M | AVCODES |
| 5196 | MM | Manasik Aviation Company | ICAO: MNM, Callsign: Manasik, IATA Desigantor changed to XN*. | SA | AVCODES |
| 5197 | MMA | Metro Manila Airways International, Inc. | | RP | AVCODES |
| 5198 | MMA | Myanmar Airways International Company Ltd. | IATA: 8M, Callsign: Myanmar, IATA Prefix: 599, | MYA | AVCODES |
| 5199 | MMA | Mondair | Callsign: Mondair, | MA | AVCODES |
| 5200 | MMA | Montreal, Maine and Atlantic Ry. Ltd. | added 4/2003; 7/2005 | | NAKINA |
