| 3701 | MHMJ | MITUSA H & M INC | | | SCAC4 |
| 3702 | MHML | MALUEG, M H TRUCKING CO LLC | | | SCAC4 |
| 3703 | MHMM | M H MOVING AND STORAGE INC | | | SCAC4 |
| 3704 | MHMN | METALTECH-OME | | | SCAC4 |
| 3705 | MHMR | METHODS & MATERIALS INC | | | SCAC4 |
| 3706 | MHMS | MONARCH MESSENGER SERVICES LTD | | | SCAC4 |
| 3707 | MHMT | MOHIMA TRANSPORT | | | SCAC4 |
| 3708 | MHMU | MICHAEL HUBER MUNCHEN GMBH | | | SCAC4 |
| 3709 | MHMX | Miner-Hillard Milling Co. | added 10/1963; 7/1965-10/1966; eliminated 4/1967 | | NAKINA |
| 3710 | MHMX | Miner-Hillard Milling Co. | 7/65-10/66; eliminated 4/67 | | NRHS |
| 3711 | MHMX | MINER-HILLARD MILLING CO. | | | PWRC |
| 3712 | MHN | Manhattan Air Limited | Callsign: Manhattan, | GB | AVCODES |
| 3713 | MHN | Manhattan Air | | | ICAO1 |
| 3714 | MHNA | MACHINE CARRIERS | | | SCAC4 |
| 3715 | MHNC | MERCHANTS OF CALIFORNIA, Merchants Transportation of California, INC | | | SCAC1 |
| 3716 | MHNK | MCHONE TRUCKING INC | | | SCAC4 |
| 3717 | MHNO | MARCHAND OIL CO INC | | | SCAC4 |
| 3718 | MHNY | MAHANA | | | SCAC4 |
| 3719 | MHO | Mokulele Airlines LLC | IATA: MW, Callsign: Mahalo, IATA Prefix: 415, ICAO designator changed from MUL. ICAO callsign changed from Mokulele. | USA | AVCODES |
| 3720 | MHOA | MARCHIO, ALFREDO | | | SCAC4 |
| 3721 | MHOL | MAHER OIL COMPANY INC | | | SCAC4 |
| 3722 | MHOS | MAIN HEATING OIL & SERVICE INC | | | SCAC4 |
| 3723 | MHOV | MHO MOVERS LLC | | | SCAC4 |
| 3724 | MHPA | M & H PROBING SYSTEMS INC | | | SCAC4 |
| 3725 | MHPD | MADAWAS | | | SCAC4 |
| 3726 | MHPF | MAESTRO SHIPPING (PACIFIC) SA | | | SCAC4 |
| 3727 | MHPH | MEDICINE HAT PILOT CAR & HOT SHOT S | | | SCAC4 |
| 3728 | MHPL | MARSHALL, TP LLC | | | SCAC4 |
| 3729 | MHPM | MARSH PETROLEUM CO | | | SCAC4 |
| 3730 | MHPR | MEIER, HANS PETER | | | SCAC4 |
| 3731 | MHQ | Skargardshavets Helikoptertjanst AB (SHT) | Callsign: Helicare, | FIN | AVCODES |
| 3732 | MHQT | MITCHELL TRANSPORTATION SERVICES IN | | | SCAC4 |
| 3733 | MHQU | U.S. DEPT. OF DEFENSE - MILITARY SEALIFT COMMAND HQ WASHINGTON DC | | | PWRC |
| 3734 | MHQU | Military Sealift Command | | | RSRV |
| 3735 | MHQU | MILITARY SEALIFT COMMAND HEADQUARTE | | | SCAC4 |
| 3736 | MHQZ | U.S. DEPT. OF DEFENSE - MILITARY SEALIFT COMMAND | | | PWRC |
| 3737 | MHQZ | Military Sealift Command | | | RSRV |
| 3738 | MHQZ | MILITARY SEALIFT COMMAND | | | SCAC4 |
| 3739 | MHRB | MARTIN, HAROLD B INC | | | SCAC4 |
| 3740 | MHRE | MHART EXPRESS INC | | | SCAC4 |
| 3741 | MHRI | MYERS, HAROLD INC | | | SCAC4 |
| 3742 | MHRM | MAHER, M G & CO INC | | | SCAC4 |
| 3743 | MHRO | MOHR OIL COMPANY INC | | | SCAC4 |
| 3744 | MHRR | Mahanoy and Hazleton Ry., Inc. | eliminated 10/86 | | NRHS |
| 3745 | MHRS | M V Z HUMBERTO ROSAS MACEDO | | | SCAC4 |
| 3746 | MHRV | MICHAELS, R INC | | | SCAC4 |
| 3747 | MHRX | Mile-High Railcar Services, Inc. | added 1/1988; eliminated 1/1993; eliminated 4/1993; 1/1994-7/2005 (not listed) | | NAKINA |
| 3748 | MHRX | Mile-High Railcar Leasing, Inc. | added 1/1980; 1/1980; eliminated 1/1988 | | NAKINA |
| 3749 | MHRX | Mile-High Railcar Leasing, Inc. | added 1/80; 1/80; eliminated 1/88 | | NRHS |
| 3750 | MHRX | Mile-High Railcar Services, Inc. | added 1/88; eliminated 1/93; eliminated 4/93; 1/94-7/2000 | | NRHS |
| 3751 | MHRX | MILE-HIGH RAILCAR SERVICES, INC. | | | PWRC |
| 3752 | MHRX | Mile-High Railcar Services | | | RSRV |
| 3753 | MHRX | MILE-HIGH RAILCAR SERVICES, INC. | | | SCAC4 |
| 3754 | MHS | Air Memphis | Callsign: Air Memphis, | ET | AVCODES |
| 3755 | MHS | Air Memphis | | | ICAO1 |
| 3756 | MHSA | MASTHEAD SHIPPING SA | | | SCAC4 |
| 3757 | MHSB | MH SHIPPING INC | | | SCAC4 |
| 3758 | MHSF | Morehead & South Fork R.R. Co., Inc. | added 7/2008; eliminated 10/2008 | | NAKINA |
| 3759 | MHSF | MOREHEAD & SOUTH FORK RAILROAD CO., INC. | | | PWRC |
| 3760 | MHSF | MOREHEAD & SOUTH FORK RAILROAD CO I | | | SCAC4 |
| 3761 | MHSH | MYTRAK HEALTH SYSTEM INC | | | SCAC4 |
| 3762 | MHSI | MOOSELY HOTSHOT SERVICES INC | | | SCAC4 |
| 3763 | MHSK | MOBILE HOME SERVICE & TRANSPORTING | | | SCAC4 |
| 3764 | MHSL | MATERIAL HANDLING SOURCE | | | SCAC4 |
| 3765 | MHSQ | MATHIS TRUCKING | | | SCAC4 |
| 3766 | MHSS | MARLETT HOT SHOT SERVICE | | | SCAC4 |
| 3767 | MHST | MESHOPPE | | | SCAC4 |
| 3768 | MHSW | MONARCH HOT SHOT | | | SCAC4 |
| 3769 | MHSX | Midvale-Heppenstall Co. | added 10/1965; 10/1966-4/1970; eliminated 1/1971 | | NAKINA |
| 3770 | MHSX | Midvale-Heppenstall Co. | added 10/65; 10/66-4/70; eliminated 1/71 | | NRHS |
| 3771 | MHSX | MID-VALE HEPPENSTALL CO. | | | PWRC |
| 3772 | MHTA | MINNIE HOMES TENT TRAILERS | | | SCAC4 |
| 3773 | MHTB | MICHEALS TRUCKING | | | SCAC4 |
| 3774 | MHTD | MCCUTCHEON TRANSPORT LTD | | | SCAC4 |
| 3775 | MHTG | MULLER, H TRUCKING INC | | | SCAC4 |
| 3776 | MHTI | MOOSEHEAD TRANSPORTATION INC | | | SCAC4 |
| 3777 | MHTL | METHANOL HOLDINGS (TRINIDAD) LIMITE | | | SCAC4 |
| 3778 | MHTM | MAHTOMEDI TRUCKING INC | | | SCAC4 |
| 3779 | MHTN | MILE HIGH TRANSPORTATION SERVICES I | | | SCAC4 |
| 3780 | MHTR | MESHOPPEN TRANSPORT INC | | | SCAC4 |
| 3781 | MHTV | MATHIS TRANSPORTATION SERVICES | | | SCAC4 |
| 3782 | MHTW | MT HOPE TRUCKING COMPANY INC | | | SCAC4 |
| 3783 | MHTX | Mangels, Herold Co., Inc. | 7/1930-10/1957; eliminated 4/1960 | | NAKINA |
| 3784 | MHTX | Mangels, Herold Co., Inc. | 4/38-10/57 | | NRHS |
| 3785 | MHTX | MANGELS, HEROLD CO., INC. | | | PWRC |
| 3786 | MHTY | M & H TRANSPORTATION | | | SCAC4 |
| 3787 | MHU | Air Memphis | Callsign: Memphis Uganda, | EAU | AVCODES |
| 3788 | MHU | Air Memphis | | | ICAO1 |
| 3789 | MHUB | MENDOZA, HUBER | | | SCAC4 |
| 3790 | MHUF | MAPLEHURST FARMS INC | | | SCAC4 |
| 3791 | MHUK | MILLER, CHUCK | | | SCAC4 |
| 3792 | MHV | MHS Aviation GmbH | IATA: M2, Callsign: Snowcap, | D | AVCODES |
| 3793 | MHVG | MülheimerVerkersgesellschaft mbH | | DE | VKM |
| 3794 | MHVI | MOHICAN MOVING & STORAGE INC | | | SCAC4 |
| 3795 | MHVK | MÁV Hajdú Vasútépítõ Kft. | | H | TRAFFIC |
| 3796 | MHVP | MHT | | | SCAC4 |
| 3797 | MHWA | Mohawk, Adirondack & Northern R.R. Corp. | 1/1994; added 1/1996; 7/2000-7/2005; eliminated 10/2006 | | NAKINA |
| 3798 | MHWA | Mohawk, Adirondack & Northern R.R. Corp. | 1/94; added 1/96; 7/2000 | | NRHS |
| 3799 | MHWA | MOHAWK, ADIRONDACK & NORTHERN RAILROAD CORP. | | | PWRC |
| 3800 | MHWA | Mohawk, Adirondack and Northern Railroad | | | RSRV |
