| 5501 | MMR | Monair SA | Callsign: Monair, | CH | AVCODES |
| 5502 | MMR | Musrata Air Transport | | | ICAO1 |
| 5503 | MMR | MINNESOTA & MANITOBA RAILROAD | | | PWRC |
| 5504 | MMR | MMRailservice GmbH | | DE | VKM |
| 5505 | MMRC | M & M TRUCKING | | | SCAC4 |
| 5506 | MMRD | M S M TRANSPORT INC | | | SCAC4 |
| 5507 | MMRG | MARTIN, THOMAS E TRUCKING | | | SCAC4 |
| 5508 | MMRL | M M RANCH | | | SCAC4 |
| 5509 | MMRM | MCR MICROCOMPUTER RENTALS | | | SCAC4 |
| 5510 | MMRO | MONTEMAY | | | SCAC4 |
| 5511 | MMRR | Mid-Michigan R.R., Inc. | added 4/1988; 1/1994-7/2005 | | NAKINA |
| 5512 | MMRR | Mid-Michigan R.R., Inc. | added 4/88; 1/94-7/2000 | | NRHS |
| 5513 | MMRR | MID-MICHIGAN RAILROAD, INC. | | | PWRC |
| 5514 | MMRR | Mid-Michigan Railroad | | | RSRV |
| 5515 | MMRR | MID-MICHIGAN RAILROAD INC | | | SCAC4 |
| 5516 | MMRR | Mid Michigan Railroad | | USA | TRAFFIC |
| 5517 | MMRS | MMR EXPRESS INC | | | SCAC4 |
| 5518 | MMRT | MMRC TRUCKING INC | | | SCAC4 |
| 5519 | MMRTC | Makkah Mass Rail Transit Company | | SA | TRAFFIC |
| 5520 | MMRU | MAINSTREAM ENGINEERING CORPORATION | | USA | BIC |
| 5521 | MMRW | M & M TRUCKING INC | | | SCAC4 |
| 5522 | MMRX | Double M Ranch Enterprises | 1/1994-7/2005 (not listed) | | NAKINA |
| 5523 | MMRX | McMurrey Refining Co. | 7/1937 (not listed) | | NAKINA |
| 5524 | MMRX | Double M Ranch Enterprises | 1/94-7/2000 | | NRHS |
| 5525 | MMRX | *MCMURREY REFINING CO. | | | PWRC |
| 5526 | MMRX | +DOUBLE M RANCH ENTERPRISES | | | PWRC |
| 5527 | MMRX | Double M Ranch Enterprises | | | RSRV |
| 5528 | MMS | Saad (A320) Ltd | Callsign: Musaad Air, | CAY | AVCODES |
| 5529 | MMS | SAAD (A320) Limited | | | ICAO1 |
| 5530 | MMSB | MMS TRANSPORTATION | | | SCAC4 |
| 5531 | MMSC | MITCHELL MILL SYSTEMS CANADA LTD | | | SCAC4 |
| 5532 | MMSD | METHODE MEXIC | | | SCAC4 |
| 5533 | MMSE | MONRO MOVING & STORAGE CO INC | | | SCAC4 |
| 5534 | MMSF | MMS TRUCKING INC | | | SCAC4 |
| 5535 | MMSG | MORRISON MOVING & STORAGE CO INC | | | SCAC4 |
| 5536 | MMSH | MILLION MILES SHIPPING LTD | | | SCAC4 |
| 5537 | MMSI | MIDWEST MOTORCYCLE SETUPS INC | | | SCAC4 |
| 5538 | MMSL | MOBILEMED SUPP | | | SCAC4 |
| 5539 | MMSM | MMS COMPANY LTD | | | SCAC4 |
| 5540 | MMSO | METCALF MOVING & STORAGE CO INC | | | SCAC4 |
| 5541 | MMSP | MACLEAN, M S TRANSPORT LTD | | | SCAC4 |
| 5542 | MMSR | MIDWAY MOBILE SERVICE INC | | | SCAC4 |
| 5543 | MMSS | MAMS MACHINE AND TOOL INC | | | SCAC4 |
| 5544 | MMSU | MUSTANG CONTAINER SALES | | | SCAC4 |
| 5545 | MMSV | MELONE MOTOR SERVICE INC | | | SCAC4 |
| 5546 | MMSX | Blue Circle Inc. | added 7/1983; eliminated 4/1987 | | NAKINA |
| 5547 | MMSX | Martin Marietta Corp. | added 1/1979; 1/1980; eliminated 7/1983 | | NAKINA |
| 5548 | MMSX | Martin Marietta Cement, Division of Martin Marietta Corp. | added 1/1975; 1/1975; eliminated 1/1979 | | NAKINA |
| 5549 | MMSX | Martin Marietta Cement, Division of Martin Marietta Corp. | added 1/75; 1/75; eliminated 1/79 | | NRHS |
| 5550 | MMSX | Martin Marietta Corp. | added 1/79; 1/80 | | NRHS |
| 5551 | MMSX | Blue Circle Inc. | eliminated 4/87 | | NRHS |
| 5552 | MMSX | BLUE CIRCLE INC. {MARTIN MARIETTA CORP.] | | | PWRC |
| 5553 | MMSX | Blue Circle | | | RSRV |
| 5554 | MMSY | MOORE MOVING & STORAGE SYSTEMS | | | SCAC4 |
| 5555 | MMSZ | MARTIN MARIETTA SYSTEMS, INC. | | | PWRC |
| 5556 | MMT | SAM Intercontinental Group S.A. | Callsign: Sam Inter, | RMM | AVCODES |
| 5557 | MMT | Mission Mountain R.R. | 7/2005; added 4/2008 | | NAKINA |
| 5558 | MMT | MISSION MOUNTAIN RAILROAD | | | PWRC |
| 5559 | MMT | MISSION MOUNTAIN RAILROAD | | | SCAC4 |
| 5560 | MMTC | M & M BROS TRUCKING CO | | | SCAC4 |
| 5561 | MMTC | Metro Manila Transit Corporation | | RP | TRAFFIC |
| 5562 | MMTD | M & M TRUCKING COMPANY INC | | | SCAC4 |
| 5563 | MMTE | MMT EXPRESS INCORPORATED | | | SCAC4 |
| 5564 | MMTF | M & M TRANSPORT | | | SCAC4 |
| 5565 | MMTK | MONMOUTH TRUCKING INC | | | SCAC4 |
| 5566 | MMTM | M M TRANSPORTES | | | SCAC4 |
| 5567 | MMTN | M & M TRUCKING | | | SCAC4 |
| 5568 | MMTO | M & M TRANSPORT | | | SCAC4 |
| 5569 | MMTQ | M & M TRANS | | | SCAC4 |
| 5570 | MMTS | MILES MOTOR TRANSPORT SYSTEMS | | | PWRC |
| 5571 | MMU | Roadrunner Aviation | Callsign: Sky Tour, | USA | AVCODES |
| 5572 | MMUB | MILLBANK MATERIALS USA | | | SCAC4 |
| 5573 | MMUG | MILAM TRUCKING | | | SCAC4 |
| 5574 | MMUL | MCMULLEN TRANSPORTATION INC | | | SCAC4 |
| 5575 | MMUN | MARMU | | | SCAC4 |
| 5576 | MMUP | MOE-MENTUM TRANSPORTATION INC | | | SCAC4 |
| 5577 | MMUR | MACCHIO, MURRAY | | | SCAC4 |
| 5578 | MMUV | MMC | | | SCAC4 |
| 5579 | MMV | Magyar Magánvasút ZRT | | H | TRAFFIC |
| 5580 | MMV | Magyar Magánvasút ZRt. | | HU | VKM |
| 5581 | MMVA | MOORE MOVING SYSTEMS INC | | | SCAC4 |
| 5582 | MMVC | MARATHON MOVING COMPANY INC | | | SCAC4 |
| 5583 | MMVD | MILLERS MARINE SERVICE INC | | | SCAC4 |
| 5584 | MMVG | MOUNTAINM | | | SCAC4 |
| 5585 | MMVH | M & M SERVICE | | | SCAC4 |
| 5586 | MMVI | MASTERSON MOVING & STORAGE CORPORAT | | | SCAC4 |
| 5587 | MMVK | VIRGINIA MCMORROW | | | SCAC3 |
| 5588 | MMVM | MONARC | | | SCAC4 |
| 5589 | MMVO | MOORE MOVING & STORAGE | | | SCAC4 |
| 5590 | MMVT | MERIT MOVING SYSTEMS INC (TEMECULA) | | | SCAC4 |
| 5591 | MMVTA | Mid Mon Valley Transit Authority | | US-PA | TRAFFIC |
| 5592 | MMWB | MOM TWO (2) B | | | SCAC4 |
| 5593 | MMWD | M & M WORLDWIDE INC | | | SCAC4 |
| 5594 | MMWI | MARTECH MOTOR WINDING LTD | | | SCAC4 |
| 5595 | MMWK | MODERN MACHINE WORKS INC | | | SCAC4 |
| 5596 | MMWT | MONTANA MIDWEST INC | | | SCAC4 |
| 5597 | MMWW | MASTER MACHINE (WINDSOR) LTD | | | SCAC4 |
| 5598 | MMWX | MIDWEST MINERALS & RAIL, LLC | | | PWRC |
| 5599 | MMWX | MIDWES | | | SCAC4 |
| 5600 | MMX | Airmax S.A. | IATA: X8, Callsign: Perumax, IATA Prefix: 658, | PE | AVCODES |
