| 1101 | MBSC | MAR-BAX SHIRT CO INC | | | SCAC4 |
| 1102 | MBSE | MUEBLES SEPULVEDA VILLAREAL SA DE C | | | SCAC4 |
| 1103 | MBSG | METRO BOBCAT SALES | | | SCAC4 |
| 1104 | MBSI | MARTINI BROKERAGE SERVICES INC | | | SCAC4 |
| 1105 | MBSL | MetroBus St.Louis | | USA | TRAFFIC |
| 1106 | MBST | MC BUSINESS SOLUTIONS | | | SCAC4 |
| 1107 | MBSU | M S D LEVANT SHIPPING S L | | | SCAC4 |
| 1108 | MBSX | Mid-South Bulk Services, Inc. | added 4/2000; 7/2000-7/2005 | | NAKINA |
| 1109 | MBSX | M.B. Suydam Division, Pittsburgh Plate Glass Co. | 4/1947-1/1952; eliminated 4/1954; 7/1954 | | NAKINA |
| 1110 | MBSX | M.B. Suydam Co. | 7/1930-1/1946 | | NAKINA |
| 1111 | MBSX | M.B. Suydam Co. | Apr-38 | | NRHS |
| 1112 | MBSX | M.B. Suydam Division, Pittsburgh Plate Glass Co. | 1/52; eliminated 4/54 | | NRHS |
| 1113 | MBSX | Mid-South Bulk Services, Inc. | added 4/2000; 7/2000 | | NRHS |
| 1114 | MBSX | *M. B. SUYDAM DIV., PITTSBURGH PLATE GLASS CO. | | | PWRC |
| 1115 | MBSX | +MID-SOUTH BULK SERVICES, INC. | | | PWRC |
| 1116 | MBSX | Mid-South Bulk Services | | | RSRV |
| 1117 | MBSX | MID-SOUTH BULK SERVICES INC | | | SCAC4 |
| 1118 | MBSY | MCGRATH, B & SONS LTD | | | SCAC4 |
| 1119 | MBT | Vias Aereas Manabitas CIA Ltda. | Callsign: Manabitas, | EC | AVCODES |
| 1120 | MBT | Province of Manitoba, Air Services Branch | Callsign: Manitoba, | CDN | AVCODES |
| 1121 | MBT | Marianna & Blountstown R.R. Co. | added 11/1973; 1/1975; eliminated 1/1976; 1/1980 | | NAKINA |
| 1122 | MBT | Marianna & Blountstown R.R. Co. | added 11/73; 1/75-1/80 | | NRHS |
| 1123 | MBT | MARIANA & BLOUNTSTOWN RAILROAD CO. | | | PWRC |
| 1124 | MBT | Marianna and Blountstown Railroad | | | RSRV |
| 1125 | MBTA | *M & B TRANSPORT INC. | | | PWRC |
| 1126 | MBTA | *MASSACHUSETTS BAY TRANSIT AUTHORITY | | | PWRC |
| 1127 | MBTA | M B T TRANSPORT INC | | | SCAC4 |
| 1128 | MBTA | Massachusetts Bay Transportation Authority | | USA | TRAFFIC |
| 1129 | MBTB | MBT 2002 | | | SCAC4 |
| 1130 | MBTC | M B T INC | | | SCAC4 |
| 1131 | MBTE | M B TRANSPORT ENTERPRISES INC | | | SCAC4 |
| 1132 | MBTF | MB2 LOGISTICS LLC | | | SCAC4 |
| 1133 | MBTI | M B TRANSPORT INC | | | SCAC4 |
| 1134 | MBTJ | MANGIARDI BROTHERS TRUCKING INC | | | SCAC4 |
| 1135 | MBTK | MORROW, BILL TRUCKING | | | SCAC4 |
| 1136 | MBTL | MAISLIN BROS TRANSP LTD | | | PWRC |
| 1137 | MBTL | MCCOMBS TRANSPORT LLC | | | SCAC4 |
| 1138 | MBTN | MACDONALD, BOB TRUCKING | | | SCAC4 |
| 1139 | MBTO | MAL-B TRANSPORT INC | | | SCAC4 |
| 1140 | MBTU | MULTIBOXX LIMITED | | HK | BIC |
| 1141 | MBTX | Massachusetts Bay Transportation Authority | added 10/2002; 7/2005 | | NAKINA |
| 1142 | MBTX | MASSACHUSETTS BAY TRANSPORTATION AUTHORITY | | | PWRC |
| 1143 | MBTX | Massachusetts Bay Transportation Authority | | | RSRV |
| 1144 | MBTX | MASSACHU | | | SCAC4 |
| 1145 | MBTY | MBT TRANSPORT LLC | | | SCAC4 |
| 1146 | MBU | Marabu Airlines OÜ | Callsign: Marabu, Planned start up with 3 x A320-200N | EST | AVCODES |
| 1147 | MBUC | MB TRUCKING | | | SCAC4 |
| 1148 | MBUG | MB TRUCKING L C | | | SCAC4 |
| 1149 | MBUL | MARTIN BENCHER USA LLC | | | SCAC4 |
| 1150 | MBUS | Museum Buurtspoorweg | | NL | TRAFFIC |
| 1151 | MBUW | MAESTRO BULK | | | SCAC4 |
| 1152 | MBUY | MOE'S BUY SELL TRADE | | | SCAC4 |
| 1153 | MBV | Aeriantur-M | Callsign: Aerem, | MD | AVCODES |
| 1154 | MBV | Aeriantur-M | | | ICAO1 |
| 1155 | MBV | Malmbanans Vänner | | SE | VKM |
| 1156 | MBVA | Flecken Bruchhausen-Vilsen | | DE | VKM |
| 1157 | MBVN | MTB AUTOMOTIVE TRANSPORTATION INC | | | SCAC4 |
| 1158 | MBW | Zambia Airways Ltd. | Callsign: Zambiana, | Z | AVCODES |
| 1159 | MBWI | MERTAUGH BOAT WORKS INC | | | SCAC4 |
| 1160 | MBWL | MEDEIROS BOAT WORKS LIMITED | | | SCAC4 |
| 1161 | MBWS | MISSOURI BASIN WELL SERVICE INC | | | SCAC4 |
| 1162 | MBWT | MITCHUM, B W TRUCKING CO INC | | | SCAC4 |
| 1163 | MBWU | MAX BOEGL STIFTUNG & CO KG | | D | BIC |
| 1164 | MBX | Montrose Beef Co. | 1/1946-10/1957; eliminated 4/1961 | | NAKINA |
| 1165 | MBX | Mechling Bros. Chemicals, a Division of General Chemical Co. | 7/1937-4/1938 | | NAKINA |
| 1166 | MBX | Mechling Bros. Chemical Co. | 7/1935 | | NAKINA |
| 1167 | MBX | Montrose Beef Co. | 1/52-10/57; eliminated 4/61 | | NRHS |
| 1168 | MBX | Mechling Bros. Chemicals, a Division of General Chemical Co. | Apr-38 | | NRHS |
| 1169 | MBX | *MECHLING BROS. CHEMICALS, DIV. GENERAL CHEMICAL CO. | | | PWRC |
| 1170 | MBX | *MONTROSE BEEF CO. | | | PWRC |
| 1171 | MBXB | MBX LOGISTICS CANADA CO ( | | | SCAC4 |
| 1172 | MBXD | MBX LOGISTIC INC | | | SCAC4 |
| 1173 | MBXG | MBX LOGISTICS CANADA CO | | | SCAC4 |
| 1174 | MBXJ | MAL-BROS TRANSPORTATION LLC | | | SCAC4 |
| 1175 | MBXL | MBT COURIER LLC | | | SCAC4 |
| 1176 | MBXM | MB TRANSPORTATION LLC | | | SCAC4 |
| 1177 | MBXN | MBS TRANSPORTATION | | | SCAC4 |
| 1178 | MBXO | MBX LOGISTICS CANADA CO | | | SCAC4 |
| 1179 | MBXQ | MOBILE TRANSPORT | | | SCAC4 |
| 1180 | MBXS | MBX LOGISTICS LLC | | | SCAC4 |
| 1181 | MBXU | MOBILBOX CONTAINER TRADING LTD | | H | BIC |
| 1182 | MBXU | MOBILEBOX CONTAINER TRADING LTD | | | SCAC4 |
| 1183 | MBY | MILLER BREWERY | | | PWRC |
| 1184 | MBYD | MILLER, BILLY D | | | SCAC4 |
| 1185 | MBYG | MELBY, GERALD | | | SCAC4 |
| 1186 | MBYK | M BOYS TRUCKING | | | SCAC4 |
| 1187 | MBYT | M & B YACHT TRANSPORT INC | | | SCAC4 |
| 1188 | MBYY | MATTRESS BOYZ | | | SCAC4 |
| 1189 | MBZE | MOUNTAIN BREEZE FARM | | | SCAC4 |
| 1190 | MBZF | MOUNTAIN BREEZE FARMS INC | | | SCAC4 |
| 1191 | MBZS | MLADOBOLESLAVSKÝ ŽELEZNIČNÍ SPOLEK | | CZ | VKM |
| 1192 | MC | Air Mobility Command (AMC) | ICAO: RCH, Callsign: Reach, | USA | AVCODES |
| 1193 | MC | Air Mobility Command | ICAO: USM, | USA | AVCODES |
| 1194 | MC | Civil Aviation Authority Flying Unit | ICAO: CFU, Callsign: Minair, Designator MC recalled by IATA | GB | AVCODES |
| 1195 | MC | Maine Coast R.R. Corp. | added 10/1992; eliminated 10/1993; 1/1994 (not listed); eliminated 1/1997; added 10/1999; 7/2000; eliminated 7/2002 | | NAKINA |
| 1196 | MC | Michigan Central R.R. | 1/1975 | | NAKINA |
| 1197 | MC | Consolidated Rail Corp. | 1/1980 | | NAKINA |
| 1198 | MC | Michigan Central R.R. | Jan-75 | | NRHS |
| 1199 | MC | Consolidated Rail Corp. | Jan-80 | | NRHS |
| 1200 | MC | Maine Coast R.R. Corp. | added 10/92; eliminated 10/93; 1/94; eliminated 1/97; added 10/99; 7/2000 | | NRHS |
