| 1 | MDS | Med Airlines S.p.A. | IATA: M8, Callsign: Mizar, Ceased operations on 15 March 2001. | I | AVCODES |
| 2 | MDS | McNeely Charter Services, Inc. | Callsign: Mid-South, | USA | AVCODES |
| 3 | MDS | McNeely Charter Services | | | ICAO1 |
| 4 | MDS | Meridian Southern Ry., L.L.C. | 7/2000-7/2005; added 7/2006 | | NAKINA |
| 5 | MDS | Meridian Southern Ry., L.L.C. | Jul-00 | | NRHS |
| 6 | MDS | MERIDIAN SOUTHERN RAILWAY [MACON, DUBLIN & SAVANNAH RR] | | | PWRC |
| 7 | MDS | Meridian Southern Railway | | | RSRV |
| 8 | MDS | MERIDIAN SOUTHERN RAILWAY LLC | | | SCAC4 |
| 9 | MDSB | Burlington Northern Inc. | 1/1980 | | NAKINA |
| 10 | MDSB | Burlington Northern Inc. | Jan-80 | | NRHS |
| 11 | MDSB | BNSF {BURLINGTON NORTHERN RAILROAD] | | | PWRC |
| 12 | MDSB | BNSF Railway | | | RSRV |
| 13 | MDSB | MUKARNAS DENIZCILIK SAN VE TIC LTD | | | SCAC4 |
| 14 | MDSC | MCCHAIN DISTRIBUTION SYSTEMS INC | | | SCAC4 |
| 15 | MDSD | MAGNUM DIVERSIFIED SERVICES INC | | | SCAC4 |
| 16 | MDSE | MCKENNAH DISTRIBUTION SERVICES INC | | | SCAC4 |
| 17 | MDSH | MIDSHIP MARITIME S A | | | SCAC4 |
| 18 | MDSI | MID-STATE MOVING & STORAGE CO INC | | | SCAC4 |
| 19 | MDSJ | MALL DELIVERY SERVICE INC | | | SCAC4 |
| 20 | MDSK | MID STATES PACKAGING INC | | | SCAC4 |
| 21 | MDSL | MICKEY D & SON LLC | | | SCAC4 |
| 22 | MDSN | MADISON TERMINAL RAILWAY LLC | | | SCAC4 |
| 23 | MDSP | MDS EXPRESS LTD | | | SCAC4 |
| 24 | MDSPB | Mestská dopravná spoločnosť, a.s., Považská Bystrica | | SK | TRAFFIC |
| 25 | MDSR | MANNING DISTRIBUTION SERVICES INC | | | SCAC4 |
| 26 | MDSS | MID SOUTH SALES INC | | | SCAC4 |
| 27 | MDST | MIDSTATES TRUCKING COMPANY INC | | | SCAC4 |
| 28 | MDSU | QINETIQ TARGET SYSTEMS LIMITED | | GB | BIC |
| 29 | MDSU | MONDIA KIRWAN S.A. | | | SCAC4 |
| 30 | MDSV | MEDICAL DELIVERY SERVICES INC | | | SCAC4 |
| 31 | MDSX | Merchants Despatch Transportation Co. | added 4/1953; 7/1954; eliminated 1/1955; added 7/1955; eliminated 1/1956 | | NAKINA |
| 32 | MDSX | Merchants Despatch Transportation Co. | added 7/55 | | NRHS |
| 33 | MDSX | MERCHANTS DESPATCH TRANSPORTATION CORP. | | | PWRC |
| 34 | MDSY | MID STATE SYSTEMS INC | | | SCAC4 |
| 35 | MDSZ | MEDSPAN SHIPPING SERVICE INC | | | PWRC |
| 36 | MDSZ | Medspan Shipping Service | | | RSRV |
| 37 | MDSZ | MEDSPAN SHIPPING SERVICE INC | | | SCAC4 |
