| 2001 | MDHL | MENDENHALL FUEL INC | | | SCAC4 |
| 2002 | MDHM | MURIDALE SHORTHORNS | | | SCAC4 |
| 2003 | MDHN | MDS TRANSPORT INC | | | SCAC4 |
| 2004 | MDHO | MASADA HOLDINGS LTD | | | SCAC4 |
| 2005 | MDHP | MEREDITH TRANSPORT INC | | | SCAC4 |
| 2006 | MDHR | MDH RANCH INC | | | SCAC4 |
| 2007 | MDHV | MD TRACTOR & TRAILER REPAIR SERVICE | | | SCAC4 |
| 2008 | MDI | MD Flugfelagid EHF (MD Airlines Ltd.) | IATA: 1I, Callsign: Delta Ice, IATA designator changed to W3 | IS | AVCODES |
| 2009 | MDI | MD Flugfelagid EHF (MD Airlines Ltd.) | IATA: W3, Callsign: Delta Ice, IATA designator changed from 1I | IS | AVCODES |
| 2010 | MDI | IAS Medical Ltd | Callsign: Medops, | GB | AVCODES |
| 2011 | MDIB | MAST DISTRIBUTORS INC | | | SCAC4 |
| 2012 | MDIC | MH DISTRIBUTION INC | | | SCAC4 |
| 2013 | MDII | M D C | | | SCAC4 |
| 2014 | MDIJ | MARX DISTRIBUTION INC | | | SCAC4 |
| 2015 | MDIK | MDI SHELLFISH CO INC | | | SCAC4 |
| 2016 | MDIM | MADIC, M INC | | | SCAC4 |
| 2017 | MDIN | MEDINA CEDENO, JOSE FRANCISCO | | | SCAC4 |
| 2018 | MDIO | MT DIABLO RECYCLING | | | SCAC4 |
| 2019 | MDIQ | MID-ISLAND DELIVERY SYSTEMS INC | | | SCAC4 |
| 2020 | MDIR | MERCHANTS DISTRIBUTION SERVICE, LTD | | | SCAC1 |
| 2021 | MDIR | MERCHANTS DISTRIBUTION SERVICE LTD | | | SCAC4 |
| 2022 | MDIT | MEDI-DART INC | | | SCAC4 |
| 2023 | MDIU | M.D. SRL | | I | BIC |
| 2024 | MDIX | Modern Dispersions, Inc. | 7/2000-7/2005 (not listed)_ | | NAKINA |
| 2025 | MDIX | Modern Dispersions, Inc. | Jul-00 | | NRHS |
| 2026 | MDIX | MODERN DISPERSIONS INCORPORATED | | | PWRC |
| 2027 | MDIX | Modern Dispersions | | | RSRV |
| 2028 | MDIX | MODERN DISPERSIONS INC | | | SCAC4 |
| 2029 | MDIY | MDI YACHT TRANSPORT LLC | | | SCAC4 |
| 2030 | MDJ | Jaro International, S.A. | Callsign: Jaro International, Founded in 1991. Ceased operations in 2001. | RO | AVCODES |
| 2031 | MDJ | SC JeTran Air S.r.l. | Callsign: Air Romania, | RO | AVCODES |
| 2032 | MDJ | Jetran Air | | | ICAO1 |
| 2033 | MDJB | M J D BROKERAGE INC | | | SCAC4 |
| 2034 | MDJE | MOLD CAM ENGINEERING INC | | | SCAC4 |
| 2035 | MDJI | MACER DELIVERY SERVICE INC | | | SCAC4 |
| 2036 | MDJL | MADJACK ENTERPRISES LLC | | | SCAC4 |
| 2037 | MDJS | M D AND J I | | | SCAC4 |
| 2038 | MDK | Medic Air (West Africa) Ltd. | Callsign: Air Doc, | WAN | AVCODES |
| 2039 | MDK | Madikwe Charter CC | Callsign: Madikwe, | ZA | AVCODES |
| 2040 | MDKC | MEINHARDT TRUCKING LLC | | | SCAC4 |
| 2041 | MDKD | MEDINAS TRUCKING | | | SCAC4 |
| 2042 | MDKE | MOLARIUS, DAN TRUCKING | | | SCAC4 |
| 2043 | MDKG | MD TRUCKING | | | SCAC4 |
| 2044 | MDKH | MEDRANO TRUCKING | | | SCAC4 |
| 2045 | MDKI | MADINA TRUCKING INC | | | SCAC4 |
| 2046 | MDKK | GARDAU MRM STEEL, INC. (MANDAK METAL PROCESSORS DIVISION) | | | PWRC |
| 2047 | MDKK | M D S TRUCKING INC | | | SCAC4 |
| 2048 | MDKM | M & D TRUCKING | | | SCAC4 |
| 2049 | MDKN | MID-DAKOTA TRANSPORT INC | | | SCAC4 |
| 2050 | MDKS | MOERDIJK CARGO SERVICES BV | | | SCAC4 |
| 2051 | MDKU | RHENUS LOGISTICS AUSTRIA GMBH | | A | BIC |
| 2052 | MDKW | MUIRHEAD TRUCKING LIMITED | | | SCAC4 |
| 2053 | MDKX | Mandak Metal Processors Division of Gerdau MRM Steel Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 2054 | MDKX | Molasses Distributors Corp. | 7/1930 | | NAKINA |
| 2055 | MDKX | Mandak Metal Processors Division of Gerdau MRM Steel Inc. | Jul-00 | | NRHS |
| 2056 | MDKX | *MOLASSES DISTRIBUTORS CORP. | | | PWRC |
| 2057 | MDKX | +MANDAK METAL PROCESSORS DIV., GERDAU MRM STEEL INC. | | | PWRC |
| 2058 | MDKX | Gardau MRM Steel Mandak Metal Processors Division | | | RSRV |
| 2059 | MDKX | MANDAK METAL PROCESSORS DIV OF GERD | | | SCAC4 |
| 2060 | MDKY | M & D TRUCKING LLC | | | SCAC4 |
| 2061 | MDL | Mandala Airlines, PT. t/a Tigerair Mandala | IATA: RI, Callsign: Mandala, Ceased operations on 01 July 2014. Designator RI reinstated by IATA. IATA designator changed from RI*. Name changed from PT. Mandala Airlines in 2010. Founded on 17 April 1969. | RI | AVCODES |
| 2062 | MDL | Mandala Airlines | IATA: RI, Callsign: Mandala, IATA designator changed to RI. Name changed from PT. Mandala Airlines | RI | AVCODES |
| 2063 | MDL | Mandala Airlines | IATA: RI, Callsign: Mandala, Name changed from PT. Mandala Airlines. Designator RI* reinstated by IATA | RI | AVCODES |
| 2064 | MDL | PT. Mandala Airlines | IATA: RI, Callsign: Mandala, Name changed to Mandala Airlines. Designator RI* reinstated by IATA | RI | AVCODES |
| 2065 | MDL | Mandala Airlines | IATA: RI | | ICAO1 |
| 2066 | MDLC | MERCURY DIRECT LOGISTICS LLC | | | SCAC4 |
| 2067 | MDLD | MIDLAND TRANSPORT LIMITED | | | SCAC1 |
| 2068 | MDLD | MIDLAND TRANSPORT LIMITED | | | SCAC4 |
| 2069 | MDLF | MIDLAND FREIGHT SYSTEMS INC | | | SCAC4 |
| 2070 | MDLJ | MOJACK DISTRIBUTORS LLC | | | SCAC4 |
| 2071 | MDLK | MCALLISTER, DON LLC | | | SCAC4 |
| 2072 | MDLN | MAHURIN-DUVALL LINES INC | | | SCAC4 |
| 2073 | MDLQ | MAR-DALE TRANSPORT (1985) LTD | | | SCAC4 |
| 2074 | MDLR | Pennsylvania Southwestern R.R. Inc. | added 10/2003; eliminated 4/2004; added 4/2005; 7/2005 | | NAKINA |
| 2075 | MDLR | The Midland Terminal Co. | added 10/1983; 1/1994-7/2000; eliminated 10/2003 | | NAKINA |
| 2076 | MDLR | The Midland Terminal Co. | added 10/83; 1/94-7/2000 | | NRHS |
| 2077 | MDLR | PENNSYLVANIA SOUTHWESTERN RAILROAD, IMC. [MIDLAND TERMINAL COMPANY] | | | PWRC |
| 2078 | MDLR | Midland Terminal | | | RSRV |
| 2079 | MDLU | MITSUBISHI GAS CHEMICAL COMPANY INC | | J | BIC |
| 2080 | MDLU | MITSUBISHI CORPORATION | | | SCAC4 |
| 2081 | MDLV | MARTIN'S FREIGHT SYSTEMS, INC | | | SCAC1 |
| 2082 | MDLV | MIDLAND TRANSPORT LIMITED (MICHELIN | | | SCAC4 |
| 2083 | MDLW | M D LOGISTICS LLC | | | SCAC4 |
| 2084 | MDLY | MIDLAND RESOURCE RECOVERY | | | SCAC4 |
| 2085 | MDM | Mediterranean Aviation Company Ltd. d/b/a Medavia Ops | IATA: N5, Callsign: Medavia, | M | AVCODES |
| 2086 | MDM | Medavia Company | | | ICAO1 |
| 2087 | MDM | MDM-Lärmschutz Ges. f. Lärmschutz mbH | | DE | VKM |
| 2088 | MDMB | MIDWEST MOVING & STORAGE INC | | | SCAC4 |
| 2089 | MDMC | MARKO DE MEXICO S DE RL DE | | | SCAC4 |
| 2090 | MDMD | MCDERM | | | SCAC4 |
| 2091 | MDME | MARIA D - SPECIAL MARITIME ENTERPRI | | | SCAC4 |
| 2092 | MDME | Metro de Medellín | | CO | TRAFFIC |
| 2093 | MDMF | MDMF TRANSPORT INC | | | SCAC4 |
| 2094 | MDMH | MID AMERICA FREIGHT HANDLERS LLC | | | SCAC4 |
| 2095 | MDMI | M & D TERMINALS INC | | | SCAC4 |
| 2096 | MDML | MODERN MOSAIC LTD | | | SCAC4 |
| 2097 | MDML | Městská doprava Mariánské Lázně | City: Mariánské Lázně | CZ | TRAFFIC |
| 2098 | MDMM | MODERN TIME ALUMINUM 2009 LTD | | | SCAC4 |
| 2099 | MDMN | MALAHIDE DESIGN & MANUFACTURING INC | | | SCAC4 |
| 2100 | MDMO | MACDONALD MOTOSPORTS | | | SCAC4 |
