| 1 | MW | Maya Island Air | ICAO: MYD, Callsign: Myland, Designator MW recalled by IATA | BH | AVCODES |
| 2 | MW | Maya Airways | | BH | AVCODES |
| 3 | MW | C T C Air, S.A. | ICAO: CTC, Callsign: CTC, Designator MW recalled by IATA | E | AVCODES |
| 4 | MW | Mokulele Flight Service, Inc. | ICAO: BUG, Callsign: Speedbuggy, IATA Prefix: 415, ICAO designator changed to MUL. ICAO callsign changed to Mokulele. IATA designator changed from 5Z* | USA | AVCODES |
| 5 | MW | Mokulele Flight Service, Inc. | ICAO: MUL, Callsign: Mokulele, IATA Prefix: 415, ICAO designator changed to MHO. ICAO designator changed from BUG. ICAO callsign changed from Speedbuggy. IATA designator changed from 5Z* | USA | AVCODES |
| 6 | MW | Mokulele Airlines LLC | ICAO: MHO, Callsign: Mahalo, IATA Prefix: 415, ICAO designator changed from MUL. ICAO callsign changed from Mokulele. | USA | AVCODES |
| 7 | MW | Waltzing Matilda Aviation, LLC | ICAO: WZM, Callsign: Matilda, | USA | AVCODES |
| 8 | MW | Minnesota Western Ry. Co. | 7/1935-10/1957 | | NAKINA |
| 9 | MW | Minnesota Western Ry. Co. | 4/38-10/57 | | NRHS |
| 10 | MW | MINNESOTA WESTERN RWY. CO. | | | PWRC |
| 11 | MW | Metro Warszawskie Sp. z o.o. | | PL | VKM |
| 12 | MW&S | Montana, Wyoming & Southern R.R. Co. | 8/1920-7/1936 | | NAKINA |
| 13 | MW&S | MONTANA, WYOMING & SOUTHERN RAILROAD CO. | | | PWRC |
| 14 | MWA | Midwest Airlines | IATA: MY, Designator MY* recalled by IATA | ET | AVCODES |
| 15 | MWA | Midwest Airlines (Egypt) | IATA: MY | | ICAO1 |
| 16 | MWAB | MORRIS, WILLIAM & ASSOCIATES INC | | | SCAC4 |
| 17 | MWAB | Midwaggon AB | 1998 - | S | svenska-lok.se |
| 18 | MWAB | Midwaggon AB | 1998 - | S | TRAFFIC |
| 19 | MWAB | Midwaggon AB | | SE | VKM |
| 20 | MWAC | MIDWEST STEEL INC | | | SCAC4 |
| 21 | MWAG | MIDWAY MOVING & STORAGE INC | | | SCAC4 |
| 22 | MWAH | MCGILL, WAYNE | | | SCAC4 |
| 23 | MWAJ | M W A TRANSPORT | | | SCAC4 |
| 24 | MWAL | MARWALL TRANSPORT | | | SCAC4 |
| 25 | MWAO | MIDWEST AIR TECHNOLOGIES INC | | | SCAC4 |
| 26 | MWAP | MULLINS WAY | | | SCAC4 |
| 27 | MWAR | Miejskie Zakłady Autobusowe w Warszawie | | PL | TRAFFIC |
| 28 | MWAU | MEDWAY ASSETS - GESTÃO DE ATIVOS S.A. | | P | BIC |
| 29 | MWAX | Martin Marietta Materials, Inc. | added 7/1997; 7/2000-7/2005 (not listed) | | NAKINA |
| 30 | MWAX | Martin Marietta Materials, Inc. | added 7/97; 7/2000 | | NRHS |
| 31 | MWAX | MARTIN MARIETTA MATERIALS INC. [MID-WESTERN AGGREGATES, LLC.] | | | PWRC |
| 32 | MWAX | Martin Marietta Materials | | | RSRV |
| 33 | MWAX | MARTIN MARIETTA MATERIALS INC | | | SCAC4 |
| 34 | MWB | Mittelweserbahn GmbH | Bruchhausen-Vilsen | D | privat-bahn.de |
| 35 | MWB | Mittelweserbahn | | D | TRAFFIC |
| 36 | MWB | Mittelweserbahn | | DE | VKM |
| 37 | MWBC | MCCARTNEY | | | SCAC4 |
| 38 | MWBI | MANIONS WHOLESALE BUILDING SUPPLIES | | | SCAC4 |
| 39 | MWBK | MIDWES | | | SCAC4 |
| 40 | MWBL | M W BULK LLC | | | SCAC4 |
| 41 | MWBRI | Montawerke Brixlegg | | AT | VKM |
| 42 | MWBT | MICHAELS WHOLESALE BAIT INC | | | SCAC4 |
| 43 | MWBX | Midwest By-Products Co., a Division of Gilco, Inc. | added 7/1987; 1/1994; eliminated 10/1995 | | NAKINA |
| 44 | MWBX | Midwest By-Products Co. | added 7/1974; 1/1975-1/1980; eliminated 7/1987 | | NAKINA |
| 45 | MWBX | Midwest By-Products Co. | added 7/74; 1/75-1/80; eliminated 7/87 | | NRHS |
| 46 | MWBX | Midwest By-Products Co., a Division of Gilco, Inc. | added 7/87; 1/94; eliminated 10/95 | | NRHS |
| 47 | MWBX | MIDWEST BY-PRODUCTS CO., A DIVISION OF GILCO, INC. | | | PWRC |
| 48 | MWBX | Midwest By-Products | | | RSRV |
| 49 | MWCA | MID-WESTERN CAR CARRIERS INC | | | SCAC4 |
| 50 | MWCF | MIDWESTERN CARTAGE INC | | | SCAC4 |
| 51 | MWCG | MIDWEST COAST LOGISTICS INC | | | SCAC4 |
| 52 | MWCH | MIDWEST COAST LOGISTICS LLC (INTERM | | | SCAC4 |
| 53 | MWCK | MARWICK MANUFACTURING INC | | | SCAC4 |
| 54 | MWCL | Midwest Coal Handling, Inc. | 1/1994-7/2005 | | NAKINA |
| 55 | MWCL | Midwest Coal Handling, Inc. | 1/94-7/2000 | | NRHS |
| 56 | MWCL | MIDWEST COAL HANDLING, INC. | | | PWRC |
| 57 | MWCL | Midwest Coal Handling | | | RSRV |
| 58 | MWCM | MATTHEWS TRUCKING | | | SCAC4 |
| 59 | MWCO | MIDWEST COAST TRUCK BROKERAGE INC | | | SCAC4 |
| 60 | MWCQ | MLC WINDOW COMPANY INC | | | SCAC4 |
| 61 | MWCR | M W CARRIERS | | | SCAC4 |
| 62 | MWCT | MIDWEST COAST LOGISTICS LLC | | | SCAC4 |
| 63 | MWCU | MAERSK A/S | | DK | BIC |
| 64 | MWCU | A P MOLLER | | | SCAC4 |
| 65 | MWCV | MOUNTAIN WEST CONTAINER SERVICES LL | | | SCAC4 |
| 66 | MWCW | METRO WORLD COURIERS | | | SCAC4 |
| 67 | MWCX | Midwest Railcar Corp. | added 4/2000; 7/2000-7/2005 | | NAKINA |
| 68 | MWCX | Marshall Wells Co., Ltd. | 7/1937 (not listed) | | NAKINA |
| 69 | MWCX | Midwest Railcar Corp. | added 4/2000; 7/2000 | | NRHS |
| 70 | MWCX | *MARSHALL WELLS CO., LTD. | | | PWRC |
| 71 | MWCX | +MIDWEST RAILCAR CORP. [MIDWEST CENTRAL RAILROAD] | | | PWRC |
| 72 | MWCX | Midwest Railcar Corporation | | | RSRV |
| 73 | MWCX | MIDWEST RAILCAR CORPORATION | | | SCAC4 |
| 74 | MWCX | Midwest Railcar Corp. | | USA | TRAFFIC |
| 75 | MWCY | MIDWAY COLONY | | | SCAC4 |
| 76 | MWDA | MOTORWORKS DRILLING SOLUTIONS | | | SCAC4 |
| 77 | MWDD | MIDWEST DEDICATED SERVICES INC | | | SCAC4 |
| 78 | MWDE | MIDWES | | | SCAC4 |
| 79 | MWDH | MOUNTAIN WEST COMMERCIAL DRIVING SC | | | SCAC4 |
| 80 | MWDR | MIDWEST INDUSTRIES INC | | | SCAC4 |
| 81 | MWDS | MILWAUKEE DELIVERY SERVICE INC | | | SCAC4 |
| 82 | MWDX | Mid-West Despatch Car Co. | 7/1930-1/1943 | | NAKINA |
| 83 | MWDX | Mid-West Despatch Car Co. (Nickel Plate-Lackawanna Dairy Line) | 7/1923 | | NAKINA |
| 84 | MWDX | Mid-West Despatch Car Co. | 8/1920 | | NAKINA |
| 85 | MWDX | Mid-West Despatch Car Co. | Apr-38 | | NRHS |
| 86 | MWDX | MID-WEST DESPATCH CAR CO. | | | PWRC |
| 87 | MWEC | MIDWES | | | SCAC4 |
| 88 | MWED | MIDWES | | | SCAC4 |
| 89 | MWEE | MENKE, WILLIAM E TRUCKING INC | | | SCAC4 |
| 90 | MWEF | MIDWEST FUELS | | | SCAC4 |
| 91 | MWEJ | Miejski Zakład Komunikacji Wejherowo | | PL | TRAFFIC |
| 92 | MWEL | MIDWEST OIL CO INC | | | SCAC4 |
| 93 | MWEN | MCEWEN TRUCKING INC | | | SCAC4 |
| 94 | MWEP | MIDWES | | | SCAC4 |
| 95 | MWER | MEDWES | | | SCAC4 |
| 96 | MWEX | Union Refrigerator Transit Lines, a Division of General American Transportation Corp. | 7/1965-4/1970; eliminated 4/1971 | | NAKINA |
| 97 | MWEX | Mars Inc. | 4/1963 | | NAKINA |
| 98 | MWEX | Union Refrigerator Transit Lines | added 4/1963 | | NAKINA |
| 99 | MWEX | Union Refrigerator Transit Lines, a Division of General American Transportation Corp. | 1/1950-4/1961 | | NAKINA |
| 100 | MWEX | Mars Inc. | 7/1932-7/1935 | | NAKINA |
