| 1 | MA | MALEV Hungarian Airlines Public Limited Company (MALEV p.l.c.) | ICAO: MAH, Callsign: Malev, IATA Prefix: 182, Name changed to MALEV Hungarian Airlines Limited | H | AVCODES |
| 2 | MA | MAE Aircraft Management WLL | ICAO: MEN, Callsign: Rahal, IATA Prefix: 723, | BRN | AVCODES |
| 3 | MA | MALEV Hungarian Airlines Limited | ICAO: MAH, Callsign: Malev, IATA Prefix: 182, Ceased operations on 03 February 2012 and declared bankrupt on 14 February 2012. Name changed from MALEV Hungarian Airlines Public Limited Company (MALEV p.l.c.) | H | AVCODES |
| 4 | MA | Elitavia Malta Ltd | ICAO: EAU, Callsign: Elite, | M | AVCODES |
| 5 | MA | Missouri and Arkansas Ry. | 1/1941-7/1954 | | NAKINA |
| 6 | MA | Missouri and Arkansas Ry. | Jan-52 | | NRHS |
| 7 | MA | MISSOURI & ARKANSAS RWY. | | | PWRC |
| 8 | MA | MID AMERICA CHARTER LINES INC | | | SCAC4 |
| 9 | MA&C | Minneapolis, Anoka and Cuyuna Range R.R. Co. | 7/1932-4/1938 | | NAKINA |
| 10 | MA&C | Minneapolis, Anoka and Cuyuna Range Ry. Co. | 7/1930 | | NAKINA |
| 11 | MA&C | Minneapolis, Anoka and Cuyuna Range Ry. | 7/1923 | | NAKINA |
| 12 | MA&C | Minneapolis, Anoka and Cuyuna Range R.R. Co. | Apr-38 | | NRHS |
| 13 | MA&C | MINNEAPOLIS, ANOKA & CUYUNA RANGE RAILROAD CO. | | | PWRC |
| 14 | MA&PA | MARYLAND & PENNSYLVANIA | | | PWRC |
| 15 | MA&S | Maxton, Alma & Southbound R.R. Co. | 8/1920-7/1923 | | NAKINA |
| 16 | MA&S | MAXTON, ALMA & SOUTHBOUND RAILROAD CO. | | | PWRC |
| 17 | MAA | Aerotransportes Mas de Carga, S.A. de C.V. t/a MasAir | IATA: MY, Callsign: MAS Carga, IATA Prefix: 865, Founded in 1992. Commenced operations on 01/04/1992. IATA designator changed to M7. Designator MY reinstated by IATA | MEX | AVCODES |
| 18 | MAA | Aerotransportes Mas de Carga, S.A. de C.V. t/a MasAir | IATA: M7, Callsign: MAS Carga, IATA Prefix: 865, Name changed to Aerotransportes Mas de Carga, S.A. de C.V. d/b/a LATAM Cargo Mexico w.e.f. 05/05/2016. IATA designator changed from MY. Designator MY reinstated by IATA | MEX | AVCODES |
| 19 | MAA | Aerotransportes Mas de Carga, S.A. de C.V. d/b/a LATAM Cargo Mexico | IATA: M7, Callsign: MAS Carga, IATA Prefix: 865, Name reverted to Aerotransportes Mas de Carga, S.A. de C.V. t/a MasAir w.e.f. 01/12/2018. Name changed from Aerotransportes Mas de Carga, S.A. de C.V. t/a MasAir w.e.f. 05/05/2016. IATA designator changed from MY. Designator MY reinstated by IATA | MEX | AVCODES |
| 20 | MAA | Aerotransportes Mas de Carga, S.A. de C.V. t/a MasAir | IATA: M7, Callsign: MAS Carga, IATA Prefix: 865, Name changed from Aerotransportes Mas de Carga, S.A. de C.V. d/b/a LATAM Cargo Mexico w.e.f. 01/12/2018. IATA designator changed from MY. Designator MY reinstated by IATA | MEX | AVCODES |
| 21 | MAA | MasAir | IATA: M7 | | ICAO1 |
| 22 | MAA | Magma Arizona R.R. Co. | 1/1975-1/1980; eliminated 1/1994; 1/1994 (not listed); 7/2000-7/2005 | | NAKINA |
| 23 | MAA | Magma Arizona R.R. Co. | 1/75-1/80; eliminated 1/94; 7/2000 | | NRHS |
| 24 | MAA | MAGMA ARIZONA RAILROAD COMPANY | | | PWRC |
| 25 | MAA | Magma Arizona Railroad | | | RSRV |
| 26 | MAA | Magma Arizona R.R. Co. | | USA | TRAFFIC |
| 27 | MAAA | MALISA TRANSPORTATION | | | SCAC4 |
| 28 | MAAB | M & M AMERICAN INC | | | SCAC4 |
| 29 | MAAC | MAAX BATH INC | | | SCAC4 |
| 30 | MAAF | MAASS FLANGE CORPORATION | | | SCAC4 |
| 31 | MAAG | MARS TRANSPORT INC | | | SCAC4 |
| 32 | MAAI | MARC G TRANSPORT INC | | | SCAC4 |
| 33 | MAAL | MARINE ACE CO LTD | | | SCAC4 |
| 34 | MAAM | MADRIGA | | | SCAC4 |
| 35 | MAAN | MARTAINER | | | SCAC4 |
| 36 | MAAO | MARTELL, VERNON | | | SCAC4 |
| 37 | MAAT | MORALES ARREOLA, ADOLFO | | | SCAC4 |
| 38 | MAAU | REFSTROYSERVICE | | RUS | BIC |
| 39 | MAAV | MARAN GAS MARITIME INC | | | SCAC4 |
| 40 | MAAW | MARQUEZ, ALBERTO TRANSPORT INC | | | SCAC4 |
| 41 | MAAX | Maxx Leasing Co. | added 1/1981; eliminated 10/1988 | | NAKINA |
| 42 | MAAX | Maxx Leasing Co. | added 1/81; eliminated 10/88 | | NRHS |
| 43 | MAAX | *MAXX LEASING CO. | | | PWRC |
| 44 | MAAX | *MEMPHIS AREA TRANSIT AUTHORITY | | | PWRC |
| 45 | MAAX | Maxx Leasing | | | RSRV |
| 46 | MAAY | NAAYKENS TRANSPORT LIMITED | | | SCAC3 |
| 47 | MAAY | MID AMERICAN TRUCKING INC | | | SCAC4 |
| 48 | MAB | Millardair Limited | Callsign: Millardair, | CDN | AVCODES |
| 49 | MAB | Airborne LiDAR Mapping A/S | Callsign: Mapping, | DK | AVCODES |
| 50 | MAB | Millardair | | | ICAO1 |
| 51 | MAB | MALVERN BRICK & TILE | | | PWRC |
| 52 | MAB | MOORE BESTWAY TRAVEL | | | SCAC4 |
| 53 | MABA | MARKALOO DESIGNS | | | SCAC4 |
| 54 | MABB | MID ATLANTIC SERVICES LLC | | | SCAC4 |
| 55 | MABD | MID ATLANTIC XPRESS INC | | | SCAC4 |
| 56 | MABE | MABE TRUCKING CO INC | | | SCAC4 |
| 57 | MABG | MAUD SHIPPING LTD | | | SCAC4 |
| 58 | MABH | MABRY, D R INC | | | SCAC4 |
| 59 | MABI | M & A TRUCKING BROKERAGE INC | | | SCAC4 |
| 60 | MABK | MASONBRINK TRUCKING | | | SCAC4 |
| 61 | MABN | M A B TRANSPORT | | | SCAC4 |
| 62 | MABS | MABEUS ENTERPRISES INC | | | SCAC4 |
| 63 | MABST | Manhattan & Bronx Surface Transit Operating Authority | | USA | TRAFFIC |
| 64 | MABSTOA | Manhattan & Bronx Surface Transit Operating Authority | | USA | TRAFFIC |
| 65 | MABU | FIRMA SCHAUENBURG | | D | BIC |
| 66 | MABU | MOHAMED ABDUL RAHMAN AL BAHAR | | | SCAC4 |
| 67 | MABX | MA BELL | | | PWRC |
| 68 | MABY | M & A TRANSPORT SERVICES INC | | | SCAC4 |
| 69 | MAC | Malta Air Charter Company Limited | IATA: R5, Callsign: Malta Charter, Designator R5 recalled by IATA | M | AVCODES |
| 70 | MAC | Malta Air Charter Company Limited | Callsign: Malta Charter, Designator R5 recalled by IATA | M | AVCODES |
| 71 | MAC | Air Arabia Maroc | IATA: 3O, Callsign: Nawras, IATA Prefix: 452, ICAO callsign changed to Arabia Maroc | MA | AVCODES |
| 72 | MAC | Air Arabia Maroc | IATA: 3O, Callsign: Arabia Maroc, IATA Prefix: 452, ICAO callsign changed from Nawras | MA | AVCODES |
| 73 | MAC | Malta Air Charter | IATA: R5 | | ICAO1 |
| 74 | MAC | MID AMERICAN CAR | | | PWRC |
| 75 | MAC | MIDDLE ATLANTIC CONFERENCE, AGENT | | | SCAC4 |
| 76 | MACD | McDONALD'S EXPRESS LINE, INC | | | SCAC1 |
| 77 | MACEG | MACEG S.r.l. - Construzioni Generali Edili e Ferroviarie | | I | TRAFFIC |
| 78 | MACF | MODULAR AND CUSTOM CABINETS | | | SCAC4 |
| 79 | MACI | MONTANA AIR CARTAGE INC | | | SCAC4 |
| 80 | MACJ | MACCAULEY | | | SCAC4 |
| 81 | MACK | MACKENZIE TRUCKING INC | | | SCAC4 |
| 82 | MACL | MACK OIL COMPANY INC | | | SCAC4 |
| 83 | MACO | McCormick, Ashland City & Nashville R.R. Inc. | added 10/1988; eliminated 1/1993 | | NAKINA |
| 84 | MACO | McCormick, Ashland City & Nashville R.R. Inc. | added 10/88; eliminated 1/93 | | NRHS |
| 85 | MACO | RETIRED 07-28-93 ATP (370) ATP [MCCORMICK-ASHLAND CITY & NASHVILLE RR} | | | PWRC |
| 86 | MACO | MAC LOGISTICS INC | | | SCAC4 |
| 87 | MACQ | MERCURY AIR CARGO INC | | | SCAC4 |
| 88 | MACR | Minneapolis, Anoka and Cuyuna Range R.R. Co. | 1/1975 | | NAKINA |
| 89 | MACR | Minneapolis, Anoka and Cuyuna Range R.R. Co. | Jan-75 | | NRHS |
| 90 | MACR | MINNEAPOLIS, ANOKA AND CUYUNA RANGE RAILROAD CO. | | | PWRC |
| 91 | MACR | MACRO TRANSPORT SERVICES LLC | | | SCAC4 |
| 92 | MACT | MAICOT INTERNATIONAL FREIGHT LLC | | | SCAC4 |
| 93 | MACU | ADR TRASPORTI SRL | | I | BIC |
| 94 | MACU | MAS CONSOLIDATE (PVT) LTD | | | SCAC4 |
| 95 | MACW | MACWORTH TRANSPORTATION SERVICES IN | | | SCAC4 |
| 96 | MACX | Mac Acquisitions, L.P. | added 10/1996; 7/2000-7/2005 | | NAKINA |
| 97 | MACX | Fruehauf Corp. | added 11/1973; 1/1975-1/1980; eliminated 7/1983 | | NAKINA |
| 98 | MACX | Magor Railcar Division, Fruehauf Corp. | eliminated 11/1973 | | NAKINA |
| 99 | MACX | Fruehauf Railcar Division, Fruehauf Corp. | added 7/1970 | | NAKINA |
| 100 | MACX | Magor Railcar Division, Fruehauf Corp. | added 7/1968; 4/1970; eliminated 7/1970 | | NAKINA |
