| 4701 | MKTM | MCKINSEY TRUCKING | | | SCAC4 |
| 4702 | MKTR | MIKES TOWING & RECOVERY INC | | | SCAC4 |
| 4703 | MKTS | MKT SERVICES | | | SCAC4 |
| 4704 | MKTT | Union Pacific R.R. Co. | added 4/1997; 7/2000-7/2005 | | NAKINA |
| 4705 | MKTT | Missouri Pacific System | added 1/1990; 1/1994; eliminated 4/1997 | | NAKINA |
| 4706 | MKTT | Missouri-Kansas-Texas R.R. Co. | 7/1965-10/1966 & 1/1975-1/1980; eliminated 1/1990 | | NAKINA |
| 4707 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas | 4/1938-4/1961 | | NAKINA |
| 4708 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas (M.-K.-T. Lines) | 7/1923-7/1936 | | NAKINA |
| 4709 | MKTT | Missouri, Kansas & Texas Ry. of Texas (M. K. & T. Lines) | 8/1920 | | NAKINA |
| 4710 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas | 4/38-4/61 | | NRHS |
| 4711 | MKTT | Missouri-Kansas-Texas R.R. Co. | 7/65-10/66 & 1/75-1/80; eliminated 1/90 | | NRHS |
| 4712 | MKTT | Missouri Pacific System | added 1/90; 1/94; eliminated 4/97 | | NRHS |
| 4713 | MKTT | Union Pacific R.R. Co. | added 4/97; 7/2000 | | NRHS |
| 4714 | MKTT | UNION PACIFIC RAILROAD CO. [MISSOURI PACIFIC; MISSOURI, KANSAS & TEXAS RWY.; M.K. & T. LINES} | | | PWRC |
| 4715 | MKTT | Missouri-Kansas-Texas Railroad (Union Pacific Railroad) | | | RSRV |
| 4716 | MKTU | MK REFTRANS CO. LTD. | | RUS | BIC |
| 4717 | MKTV | MARK THE MOVER INC | | | SCAC4 |
| 4718 | MKTW | MACK TRUCKING INC | | | SCAC4 |
| 4719 | MKTY | MCCORKLE TRUCKING SERVICE | | | PWRC |
| 4720 | MKTZ | UP [MISSOURI PACIFIC RAILROAD] | | | PWRC |
| 4721 | MKTZ | Missouri-Kansas-Texas Railroad (Union Pacific Railroad) | | | RSRV |
| 4722 | MKTZ | UNION PACIFIC RAILROAD COMPANY | | | SCAC4 |
| 4723 | MKU | Hawaii Island Air. Inc d/b/a Island Air | IATA: WP, Callsign: Moku, Ceased operations on 11 November 2017. Name changed from Aloha Islandair, Inc. w.e.f. 11 May 2004. | USA | AVCODES |
| 4724 | MKUC | MAK AUTO AND CUSTOMS | | | SCAC4 |
| 4725 | MKUG | MACK TRUCKING | | | SCAC4 |
| 4726 | MKUK | MIKES II TRUCKING | | | SCAC4 |
| 4727 | MKUN | MANKU TRANSPORT INC | | | SCAC4 |
| 4728 | MKV | Michkov Air Services | Callsign: Luber, | RUS | AVCODES |
| 4729 | MKV | MAK Aviation Services | Ceased operations | CDN | AVCODES |
| 4730 | MKVU | {LLC "TANK-YARD"};ZIPCODE=119019 | | RUS | BIC |
| 4731 | MKVU | HIMSNAB LLC | | | SCAC4 |
| 4732 | MKWI | MKW TRANSPORTATION INC | | | SCAC4 |
| 4733 | MKX | Misko Refineries, Inc. | 7/1930 | | NAKINA |
| 4734 | MKX | MISKO REFINERIES, INC. | | | PWRC |
| 4735 | MKXC | MK TRANSPORT COMPANY | | | SCAC4 |
| 4736 | MKXN | MARGARET & KATHERINA TRANSPORT INC | | | SCAC4 |
| 4737 | MKXO | MOLAK EXPRESS LTD | | | SCAC4 |
| 4738 | MKXR | MARKET EXPRESS TRANSPORTATION, INC | | | SCAC1 |
| 4739 | MKXR | MARKET EXPRESS TRANSPORTATION INC | | | SCAC4 |
| 4740 | MKXT | MAKRO TRANSPORT | | | SCAC4 |
| 4741 | MKXY | MILES TRUCKING & EXCAVATING COMPANY | | | SCAC4 |
| 4742 | MKY | Monky Aerotaxis, S.A. | Callsign: Monky, | MEX | AVCODES |
| 4743 | MKY | Monky Aerotaxis | | | ICAO1 |
| 4744 | MKYC | MARKEY, CLIFF TRANSPORT INC | | | SCAC4 |
| 4745 | MKYD | MACKAY, DONALD | | | SCAC4 |
| 4746 | MKYL | MCKINNEY TRANSPORTATION INC | | | SCAC4 |
| 4747 | MKYM | MCKINNE | | | SCAC4 |
| 4748 | MKYT | MICKEY TOWING INC | | | SCAC4 |
| 4749 | MKYU | MACKAY CONTAINERS PTY LTD | | AUS | BIC |
| 4750 | MKYU | CALBAR PTY LTD | | | SCAC4 |
| 4751 | MKZF | MCKENZIE FARMS | | | SCAC4 |
| 4752 | MKZP | MCKENZIE TRANSPORTATION CO INC | | | SCAC4 |
| 4753 | MKZV | MCKENZIE RV TRAILERS | | | SCAC4 |
| 4754 | ML | Air Micronesia, Inc. | IATA Prefix: 939, | GUM | AVCODES |
| 4755 | ML | Olympic Aviation, S.A. | ICAO: OLY, Callsign: Olavia, Designator ML* recalled by IATA. Founded in 1971. Ceased operation in 2003. | GR | AVCODES |
| 4756 | ML | Air Mediterranee | ICAO: BIE, Callsign: Mediterranee, IATA Prefix: 853, Founded in 1997. Ceased operations on 15 February 2016. | F | AVCODES |
| 4757 | ML | African Transport Trading And Investment Co. (ATTICO) | ICAO: ETC, Callsign: Tranattico, | SUD | AVCODES |
| 4758 | ML | Midway Airlines | ICAO: MID, Callsign: Midway, Founded on 06 August 1976. Filed for Chapter 11 bankruptcy portection March 1991. Ceased operations on 13 November 1991. | USA | AVCODES |
| 4759 | ML | Malaysian-Singapore Airlines | Callsign: Emessaye (MAS), | SGP | AVCODES |
| 4760 | ML | Anglo Airlines Ltd. d/b/a Anglo Cargo Ltd. | ICAO: ANC, Callsign: Anglo, | GB | AVCODES |
| 4761 | ML | Sky Mali | ICAO: FML, Callsign: Eagle Bird, | RMM | AVCODES |
| 4762 | ML&T | Morgan's Louisiana & Texas R.R. | 4/1938-7/1954 | | NAKINA |
| 4763 | ML&T | Morgan's Louisiana & Texas R.R. (Southern Pacific Lines in Texas and Louisiana) | 8/1920-7/1936 | | NAKINA |
| 4764 | ML&T | Morgan's Louisiana & Texas R.R. | 4/38-1/52 | | NRHS |
| 4765 | ML&T | MORGAN'S LOUISIANA & TEXAS RAILROAD (SOUTHERN PACIFIC LINES IN TEXAS & LOUISIANA) | | | PWRC |
| 4766 | MLA | 40-Mile Air, Ltd. | IATA: Q5, Callsign: Mile Air, IATA chaned from 6M | USA | AVCODES |
| 4767 | MLA | 40 Mile Air | IATA: 6M, Callsign: Mile Air, IATA designator changed to Q5* | USA | AVCODES |
| 4768 | MLA | 40-Mile Air | IATA: Q5 | | ICAO1 |
| 4769 | MLAB | MADISON LOGISTICS INC | | | SCAC4 |
| 4770 | MLAC | MARVIN LUMBER AND CEDAR COMPANY | | | SCAC4 |
| 4771 | MLAD | MLT INC | | | SCAC4 |
| 4772 | MLAF | MLC TRANSPORTATION LLC | | | SCAC4 |
| 4773 | MLAI | MCL & ASSOCIATES INC | | | SCAC4 |
| 4774 | MLAJ | M & L TRANSIT | | | SCAC4 |
| 4775 | MLAK | MAK LOGISTIC LLC | | | SCAC4 |
| 4776 | MLAN | MILLENIUM CARRIERS TRUCKING LLC | | | SCAC4 |
| 4777 | MLAQ | MTM LOGISTICS INC | | | SCAC4 |
| 4778 | MLAT | Morgan’s Louisiana & Texas Railroad | Real: MLT | USA | TRAFFIC |
| 4779 | MLAU | MANUFACTURING MANAGEMENT, MALTA LTD | | M | BIC |
| 4780 | MLAU | AIR LIQUIDE MALAYSIA SDN BHD | | | SCAC4 |
| 4781 | MLAV | MAXCO DISTRIBUTORS INC | | | SCAC4 |
| 4782 | MLB | Manaf International Airways | Callsign: Manaf, | RU | AVCODES |
| 4783 | MLB | Manaf International Airways | | | ICAO1 |
| 4784 | MLBC | M L CEDAR CO INC | | | SCAC4 |
| 4785 | MLBD | MILLBROOK DISTRIBUTION SERVICES INC | | | SCAC4 |
| 4786 | MLBE | MELVILLE, L & B TRUCKING INC | | | SCAC4 |
| 4787 | MLBF | MILLAR BROOKE FARM LTD | | | SCAC4 |
| 4788 | MLBH | MANATEE LOGISTICS INC | | | SCAC4 |
| 4789 | MLBI | MERLINS TRUCK BROKERAGE INC | | | SCAC4 |
| 4790 | MLBM | MARINE LUBRICANTS INC | | | SCAC4 |
| 4791 | MLBO | MUNDILL LLC | | | SCAC4 |
| 4792 | MLBQ | MULTISERVICIOS LOGISTICA BAKER SA D | | | SCAC4 |
| 4793 | MLBS | MUELLER BRASS CO | | | SCAC4 |
| 4794 | MLBT | MILLER BROS TRUCKING | | | SCAC4 |
| 4795 | MLBV | MILLER, BA LLC | | | SCAC4 |
| 4796 | MLBYD | P.W. M&L Roman Mierzbiczak | | PL | VKM |
| 4797 | MLC | Malila Airlift | Callsign: Malila, | ZRE | AVCODES |
| 4798 | MLC | Malila Airlift | | | ICAO1 |
| 4799 | MLC | MICHIGAN LIMESTONE & CHEMICAL | | | PWRC |
| 4800 | MLCB | MEL-CO TRANSPORTATION & TRUCK BROKE | | | SCAC4 |
