| 1 | MCL | Medical Aviation Services Ltd. | Callsign: Medic, | GB | AVCODES |
| 2 | MCL | McCauley Aviation, Inc. | Callsign: Mccauley, | USA | AVCODES |
| 3 | MCL | Medical Aviation Services | | | ICAO1 |
| 4 | MCL | Mediterranian | | I | TRAFFIC |
| 5 | MCLB | MILLER-CLABORN OIL DISTRIBUTION CO | | | SCAC4 |
| 6 | MCLC | MICHAELS CARTAGE INC | | | SCAC4 |
| 7 | MCLE | MCLELLAN, ROD COMPANY | | | SCAC4 |
| 8 | MCLF | MCDONALD, LEWIS FRANK INC | | | SCAC4 |
| 9 | MCLI | MCL-MULTI CONTAINER LINE | | | SCAC4 |
| 10 | MCLJ | MCLAUGHLIN TRANSPORTATION SYSTEMS I | | | SCAC4 |
| 11 | MCLK | MCCLELLAN BROKERAGE | | | SCAC4 |
| 12 | MCLL | MCLELLAN, L S TRUCKING LTD | | | SCAC4 |
| 13 | MCLM | MCL-MULTI CONTAINER LINE INC | | | SCAC4 |
| 14 | MCLN | MacLEOD TRUCKING | | | SCAC1 |
| 15 | MCLN | MACLEOD TRUCKING | | | SCAC4 |
| 16 | MCLO | MC LOGIX INC | | | SCAC4 |
| 17 | MCLQ | METRO CONTAINER LLC | | | SCAC4 |
| 18 | MCLR | McLaughlin Line R.R. | added 7/1988; eliminated 1/1992; 1/1994-7/2005 | | NAKINA |
| 19 | MCLR | McLaughlin Line R.R. | added 7/88; eliminated 1/92; 1/94-7/2000 | | NRHS |
| 20 | MCLR | MCLAUGHLIN LINE RAILROAD | | | PWRC |
| 21 | MCLR | McLaughlin Line Railroad | | | RSRV |
| 22 | MCLR | MCLAUGHLIN LINE RAILROAD | | | SCAC4 |
| 23 | MCLS | MCCLAYS TRANSPORTATION LTD | | | SCAC4 |
| 24 | MCLT | MCLOUTH STEEL | | | PWRC |
| 25 | MCLT | MCCLAINS TRUCKING INC | | | SCAC4 |
| 26 | MCLU | BORCHARD LINES LTD | | GB | BIC |
| 27 | MCLU | BORCHARD LINES LTD | | | SCAC4 |
| 28 | MCLV | MCLAUGHLIN MOVING CO INC | | | SCAC4 |
| 29 | MCLW | MCLAUGHLIN, W J HAULAGE LIMITED | | | SCAC4 |
| 30 | MCLX | Morrison Car Leasing, Inc. | added 4/1967; 4/1970-1/1980; eliminated 10/1985 | | NAKINA |
| 31 | MCLX | North Western Refrigerator Line Co. | eliminated 7/1958 | | NAKINA |
| 32 | MCLX | North American Car Corp. | 10/1957 | | NAKINA |
| 33 | MCLX | North Western Refrigerator Line Co., A Division of North American Car Corp. | added 4/1956 | | NAKINA |
| 34 | MCLX | North Western Refrigerator Line Co. | 7/1937-7/1954; eliminated 4/1956 | | NAKINA |
| 35 | MCLX | North Western Refrigerator Line Co. | 4/38-1/52 | | NRHS |
| 36 | MCLX | North American Car Corp. | Oct-57 | | NRHS |
| 37 | MCLX | North Western Refrigerator Line Co. | eliminated 7/58 | | NRHS |
| 38 | MCLX | Morrison Car Leasing, Inc. | added 4/67; 4/70-1/80 | | NRHS |
| 39 | MCLX | *NORTH WESTERN REFRIGERATOR LINE CO., DIV NACCO | | | PWRC |
| 40 | MCLX | *MORRISON CAR LEASING, INC. | | | PWRC |
| 41 | MCLX | Morrison Car Leasing | | | RSRV |
| 42 | MCLY | McCAULEY TRUCKING COMPANY | | | SCAC1 |
| 43 | MCLY | MCCAULEY TRUCKING COMPANY, THE | | | SCAC4 |
