| 7001 | MPWQ | METRO PARK WAREHOUSES, INC | | | SCAC1 |
| 7002 | MPWQ | METRO PARK WAREHOUSES INC | | | SCAC4 |
| 7003 | MPWU | A P MOLLER | | | SCAC4 |
| 7004 | MPWX | Muscaline Power & Water | added 4/1994; 7/2000; eliminated 10/2001; 7/2005 (not listed) | | NAKINA |
| 7005 | MPWX | Meigs Pulpwood Co., Inc. | 8/1920 | | NAKINA |
| 7006 | MPWX | Muscaline Power & Water | added 4/94; 7/2000 | | NRHS |
| 7007 | MPWX | *MEIGS PULPWOOD CO., INC. | | | PWRC |
| 7008 | MPWX | +MUSCATINE POWER & WATER | | | PWRC |
| 7009 | MPWX | Muscatine Power and Water | | | RSRV |
| 7010 | MPWX | MUSCATINE POWER & WATER | | | SCAC4 |
| 7011 | MPX | Aeromexpress S.A. de C.V. | IATA: QO, Callsign: Aeromexpress, IATA Prefix: 976, | MEX | AVCODES |
| 7012 | MPX | Aeromexpress | IATA: QO | | ICAO1 |
| 7013 | MPX | Columbian Carbon Co., Magnetic Pigment Division | 1/1945-1/1952; eliminated 10/1953 | | NAKINA |
| 7014 | MPX | Magnetic Pigment Co. | 7/1937-1/1943 | | NAKINA |
| 7015 | MPX | Magnetic Pigment Co. | Apr-38 | | NRHS |
| 7016 | MPX | Columbian Carbon Co., Magnetic Pigment Division | 1/52; eliminated 10/53 | | NRHS |
| 7017 | MPX | COLUMBIAN CARBON CO., MAGNETIC PIGMENT DIV. | | | PWRC |
| 7018 | MPXD | MPX INCORPORATED | | | SCAC4 |
| 7019 | MPXE | M.A.T. PARCEL EXPRESS, INC | | | SCAC1 |
| 7020 | MPXE | M A T EXPRESS | | | SCAC4 |
| 7021 | MPXI | MISTER P EXPRESS INC | | | SCAC4 |
| 7022 | MPXL | MERCURYPD | | | SCAC4 |
| 7023 | MPXP | MAPCO EXPRESS INC | | | SCAC4 |
| 7024 | MPXQ | MTP TRANSPORT INC | | | SCAC4 |
| 7025 | MPXT | METROPOLITAN TRANSPORT LTD | | | SCAC4 |
| 7026 | MPYH | MURPHY, JOHN A | | | SCAC1 |
| 7027 | MPYP | MURPHY PIPELINE CONTRACTORS INC | | | SCAC4 |
| 7028 | MPYR | MELROSE PYROTECHNICS INC | | | SCAC4 |
| 7029 | MPYS | MUNICIPALITY OF SKAGWAY | | | SCAC4 |
| 7030 | MPYT | MURPHY TRANSPORTATION INC | | | SCAC4 |
| 7031 | MPZ | UP [MISSOURI PACIFIC RAILROAD] | | | PWRC |
| 7032 | MPZ | Missouri Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 7033 | MPZ | UNION PACIFIC RAILROAD COMPANY | | | SCAC4 |
| 7034 | MPZ | Muzeum Prumyslovych Zeleznic Mladejov | | CZ | TRAFFIC |
| 7035 | MPZS | MANTENIMIENTO DE POZOS SA DE CV | | | SCAC4 |
| 7036 | MPZX | Mineral Point Zinc Co. | 8/1920-4/1938 | | NAKINA |
| 7037 | MPZX | Mineral Point Zinc Division, The New Jersey Zinc Co. | 1/1941-10/1957; eliminated 10/1958 | | NAKINA |
| 7038 | MPZX | Mineral Point Zinc Co. | Apr-38 | | NRHS |
| 7039 | MPZX | Mineral Point Zinc Division, The New Jersey Zinc Co. | 1/52-10/57; eliminated 10/58 | | NRHS |
| 7040 | MPZX | MINERAL POINT ZINC DIV., NEW JERSEY ZINC CO. | | | PWRC |
| 7041 | MQ | American Eagle Airlines, Inc. d/b/a American Eagle | ICAO: EGF, Callsign: Eagle Flight, Name changed to Executive Airlines, Inc. | USA | AVCODES |
| 7042 | MQ | Simmons Airlines Inc. d/b/a American Eagle | ICAO: SYM, | USA | AVCODES |
| 7043 | MQ | Societa Aerea Mediterranea (SAM) | Callsign: Air Sam, | I | AVCODES |
| 7044 | MQ | Maldives Airways Ltd. | Callsign: Maldivesair, IATA designator changed to PN | MV | AVCODES |
| 7045 | MQ | American Eagle Airlines, Inc. d/b/a American Eagle | ICAO: EGF, Callsign: Eagle Flight, Name changed to Envoy Air, Inc. ICAO designator changed to ENY. ICAO Callsign changed to Envoy. Designator MQ reinstated by IATA | USA | AVCODES |
| 7046 | MQ | Envoy Air, Inc. | ICAO: ENY, Callsign: Envoy, IATA Prefix: 093, Name changed from American Eagle Airlines, Inc. d/b/a American Eagle, Inc. ICAO designator changed from EGF. ICAO Callsign changed from Eagle Flight. Designator MQ reinstated by IATA | USA | AVCODES |
| 7047 | MQAB | MAIL CONTRACTORS OF AMERICA INC (BR | | | SCAC4 |
| 7048 | MQAI | MARQUEZ TRUCKING | | | SCAC4 |
| 7049 | MQAL | MCALISTER OIL COMPANY | | | SCAC4 |
| 7050 | MQAM | MAIL CONTRACTORS OF AMERICA INC | | | SCAC4 |
| 7051 | MQAP | MARQUARD | | | SCAC4 |
| 7052 | MQAY | MAXIMUM TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 7053 | MQCA | MCCARTY, CARL | | | SCAC4 |
| 7054 | MQCB | MCBRIDE TRUCKING INC | | | SCAC4 |
| 7055 | MQCC | MAQUINARIA Y LUBRICANTES DEL NOROES | | | SCAC4 |
| 7056 | MQCD | DSR-MCCS | | | SCAC1 |
| 7057 | MQCD | MEDITERRANEAN CANADA CONT. SVC. | | | SCAC4 |
| 7058 | MQCH | MCH LLC | | | SCAC4 |
| 7059 | MQCM | M C M ENTERPRISES | | | SCAC4 |
| 7060 | MQCN | MICHOACANA H M, LA | | | SCAC4 |
| 7061 | MQCO | METRO CONSOLIDATORS | | | SCAC4 |
| 7062 | MQCR | MARINE CARGO | | | SCAC4 |
| 7063 | MQCX | Monarch Cement Co. | added 4/1980; eliminated 4/1987; 1/1994 (not listed) | | NAKINA |
| 7064 | MQCX | Marquette Co., a subsidiary of Gulf & Western Industries, Inc. | added 1/1979; 1/1980; eliminated 4/1980 | | NAKINA |
| 7065 | MQCX | Marquette Co. | eliminated 1/1979 | | NAKINA |
| 7066 | MQCX | Marquette Cement Manufacturing Co., a Division of Marquette Co. | added 10/1976 | | NAKINA |
| 7067 | MQCX | Marquette Co. | added 7/1976; eliminated 10/1976 | | NAKINA |
| 7068 | MQCX | Marquette Co. | added 7/76; eliminated 1/79 | | NRHS |
| 7069 | MQCX | Marquette Co., a subsidiary of Gulf & Western Industries, Inc. | added 1/79; 1/80; eliminated 4/80 | | NRHS |
| 7070 | MQCX | Monarch Cement Co. | added 4/80; eliminated 4/87; 1/94 | | NRHS |
| 7071 | MQCX | MONARCH CEMENT COMPANY [MARQUETTE CO.] | | | PWRC |
| 7072 | MQCX | Monarch Cement | | | RSRV |
| 7073 | MQDC | MEDICI888 LLC | | | SCAC4 |
| 7074 | MQDR | MCDONALD, BILLY J | | | SCAC4 |
| 7075 | MQET | M T E EXPRESS | | | SCAC4 |
| 7076 | MQFO | MURRAY & QUARLTERE FUEL OIL CORP | | | SCAC4 |
| 7077 | MQGB | MAR LOGISTICS LLC | | | SCAC4 |
| 7078 | MQGT | MISKIE, DAN TRUCKING | | | SCAC4 |
| 7079 | MQGX | Morrison-Quirk Grain Corp. | added 7/1973; 1/1975-1/1980 | | NAKINA |
| 7080 | MQGX | XTRA, Inc. | eliminated 1/1988 | | NAKINA |
| 7081 | MQGX | Morrison-Quirk Grain Corp. | added 7/73; 1/75-1/80 | | NRHS |
| 7082 | MQGX | XTRA, Inc. | eliminated 1/88 | | NRHS |
| 7083 | MQGX | *MORRISON-QUIRK GRAIN CORP. | | | PWRC |
| 7084 | MQGX | *RETIRED 11-24-92 ATP (1055) [XTRA INC.] | | | PWRC |
| 7085 | MQGX | Morrison-Quirk Grain Corporation | | | RSRV |
| 7086 | MQIS | MARQUIS, RON TRUCKING INC | | | SCAC4 |
| 7087 | MQIT | M I T TRANSPORT LTD | | | SCAC4 |
| 7088 | MQKN | MACKIN CONSTRUCTION CO | | | SCAC4 |
| 7089 | MQLA | MITSUBISHI LOGISTICS AMERICA CORPOR | | | SCAC4 |
| 7090 | MQLD | MONTROSE LOGISTICS LTD | | | SCAC4 |
| 7091 | MQLI | METRO LOGISTICS INC | | | SCAC4 |
| 7092 | MQLL | MILLER ENTERPRISES | | | SCAC4 |
| 7093 | MQLU | MADDOX HOLDING B V | | | SCAC4 |
| 7094 | MQMA | M M & A | | | SCAC4 |
| 7095 | MQMC | M & M TRUCKING INC | | | SCAC4 |
| 7096 | MQMI | MORRISON MARITIME INC EL SEGUNDO CA | | | SCAC4 |
| 7097 | MQMT | MONUMENT TRANSPORTATION INC | | | SCAC4 |
| 7098 | MQNA | MAC-NELS AGENCIES PTE LTD | | | SCAC4 |
| 7099 | MQNC | MTM TRANSPORTATION INC | | | SCAC4 |
| 7100 | MQNT | METRO T & C INC | | | SCAC4 |
