| 8601 | MTLA | MELTON TRUCK LINES | | | SCAC1 |
| 8602 | MTLA | MELTON TRUCK LINES INC | | | SCAC4 |
| 8603 | MTLC | MARTIN TRANS-LOGICS INC | | | SCAC4 |
| 8604 | MTLD | MICHAEL TOOL & MOLD LTD | | | SCAC4 |
| 8605 | MTLE | MODE TRANSPORTATION LLC | | | SCAC4 |
| 8606 | MTLF | MAP TRANSPORT LLC | | | SCAC4 |
| 8607 | MTLI | M E P TECHNOLOGIES INC | | | SCAC4 |
| 8608 | MTLJ | MORGAN TANK LINES | | | SCAC4 |
| 8609 | MTLL | MATTHEWS TRUCKING LLC | | | SCAC4 |
| 8610 | MTLM | MABL TRUCKING LLC. | | | SCAC4 |
| 8611 | MTLN | MERCHANTS TRUCKLOAD COMPANY, INC | | | SCAC1 |
| 8612 | MTLP | MUTUAL TRANSPORTATION SERVICES INC | | | SCAC4 |
| 8613 | MTLQ | MT. LASSEN MOTOR TRANSIT, INC | | | SCAC1 |
| 8614 | MTLR | MOTOR CITY ELECTRIC CO | | | SCAC4 |
| 8615 | MTLU | DUTCH ANTILLEAN CONTAINER LEASING LTD | | CY | BIC |
| 8616 | MTLU | MONTGOMERY TANK LINES | | | PWRC |
| 8617 | MTLU | Montgomery Tank Lines | | | RSRV |
| 8618 | MTLU | NATIONAL SHIPPING COMPANY | | | SCAC3 |
| 8619 | MTLW | MAD TRUCKING LLC | | | SCAC4 |
| 8620 | MTLX | Metal Link International, LLC | added 10/2001; eliminated 1/2004; 7/2005 (not listed) | | NAKINA |
| 8621 | MTLX | Morris & Co. Tank Line (Armour Car Lines) | 7/1923 | | NAKINA |
| 8622 | MTLX | McKenzie Tank Lines, Inc. | added 1/1964; eliminated 4/1965; 7/1965 (not listed) | | NAKINA |
| 8623 | MTLX | Morris & Co. Tank Line (Morris & Co. Refrigerator Line) | 8/1920 | | NAKINA |
| 8624 | MTLX | McKenzie Tank Lines, Inc. | eliminated 4/65; 7/65 | | NRHS |
| 8625 | MTLX | *ARMOUR CAR LINES [MORRIS & CO. TANK LINE] | | | PWRC |
| 8626 | MTLX | *MCKENZIE TANK LINES, INC. | | | PWRC |
| 8627 | MTLX | +METAL LINK INTERNATIONAL, LLC | | | PWRC |
| 8628 | MTLX | Metal Link International | | | RSRV |
| 8629 | MTLX | METAL LINK INTERNATIONAL LLC | | | SCAC4 |
| 8630 | MTLZ | MARKET TRANSPORT LTD | | | SCAC4 |
| 8631 | MTM | MTM Aviation GmbH | Callsign: Avitrans, | D | AVCODES |
| 8632 | MTM | MEMPHIS TRANSPORTATION MUSEUM | | | PWRC |
| 8633 | MTM | Museumstramway Mariazell | | A | TRAFFIC |
| 8634 | MTMA | MT MARITIME MANAGEMENT (USA) LLC | | | SCAC4 |
| 8635 | MTMB | M TWO (2) M | | | SCAC4 |
| 8636 | MTMD | MID THUMB MATERIALS INC | | | SCAC4 |
| 8637 | MTMI | Metro Transit (Minnesota) | City: Minneapolis, Saint Paul | USA | TRAFFIC |
| 8638 | MTMJ | MILITARY TRANSPORTATION MOVERS CORP | | | SCAC4 |
| 8639 | MTMR | MOTORAMA AUTO CENTER INC | | | SCAC4 |
| 8640 | MTMS | METRO MOVING AND STORAGE | | | SCAC4 |
| 8641 | MTMU | MTT SHIPPING SDN. BHD. | | MAL | BIC |
| 8642 | MTMU | MARCH, LTD | | | PWRC |
| 8643 | MTMX | Modern Track Machinery Canada Ltd. (MofW cars) | 1/1994 (not listed) | | NAKINA |
| 8644 | MTMX | Modern Track Machinery Canada Ltd. | 1/1980 | | NAKINA |
| 8645 | MTMX | Modern Track Machinery Canada Ltd. | Jan-80 | | NRHS |
| 8646 | MTMX | Modern Track Machinery Canada Ltd. (MofW cars) | Jan-94 | | NRHS |
| 8647 | MTMX | MODERN TRACK MACHINERY CANADA LTD | | | PWRC |
| 8648 | MTMX | Modern Track Machinery | | | RSRV |
| 8649 | MTN | Mountain Air Cargo, Inc. | IATA: C2, Callsign: Mountain, Designator C2* recalled by IATA. | USA | AVCODES |
| 8650 | MTN | Mountain Air Cargo, Inc. | Callsign: Mountain, Designator C2* recalled by IATA. | USA | AVCODES |
| 8651 | MTN | Mountain Air Cargo | | | ICAO1 |
| 8652 | MTNA | MATTS TRANSPORTATION INC | | | SCAC4 |
| 8653 | MTNB | MIDDLETON TRANSPORTATION COMPANY (D | | | SCAC4 |
| 8654 | MTNC | MARTINEZ RODRIGUEZ, CALIXTO | | | SCAC4 |
| 8655 | MTNE | MILTON ENTERPRISES INC | | | SCAC4 |
| 8656 | MTNH | MTN TRANSPORTATION & LOGISTICS INC | | | SCAC4 |
| 8657 | MTNI | MOORE TRANSPORTATION INCORPORATED | | | SCAC4 |
| 8658 | MTNK | M C TANK TRANSPORT INC | | | SCAC4 |
| 8659 | MTNL | MOUNTAINLAND TRANSPORTATION | | | SCAC4 |
| 8660 | MTNM | MOUNTAIN STATES MOVING AND STORAGE | | | SCAC4 |
| 8661 | MTNM | Mount Newman Mining Railway | | AUS | TRAFFIC |
| 8662 | MTNN | MYERS TRANSPORTATION GROUP LLC, THE | | | SCAC4 |
| 8663 | MTNO | METALLIC EVOLUTION INC | | | SCAC4 |
| 8664 | MTNQ | MOUNTAIN TRUCKING | | | SCAC4 |
| 8665 | MTNR | Mississippi Tennessee R.R. LLC | 7/2005 | | NAKINA |
| 8666 | MTNR | MISSISSIPPI TENESSEE RAILROAD LLC | | | PWRC |
| 8667 | MTNR | MISSISSIPPI TENNESSEE RAILROAD LLC | | | SCAC4 |
| 8668 | MTNS | MONTEREY TRANSFER & STORAGE INC | | | SCAC4 |
| 8669 | MTNU | MEEBERG HOLDING B.V. | | NL | BIC |
| 8670 | MTNV | MOUNTAIN VIEW MOVING & STORAGE | | | SCAC4 |
| 8671 | MTNX | Rocky Mountain Transportation Services | added 4/1996; 7/2000-7/2005 | | NAKINA |
| 8672 | MTNX | Rocky Mountain Transportation Services | added 4/96; 7/2000 | | NRHS |
| 8673 | MTNX | ROCKY MOUNTAIN TRANSPORTATION SERVICES | | | PWRC |
| 8674 | MTNX | Rocky Mountain Transportation Services | | | RSRV |
| 8675 | MTNY | MCCULLOUGH TRANSPORTATION SERVICES | | | SCAC4 |
| 8676 | MTO | Manitoulin Air Services Ltd. | Callsign: Manitoulin, | CDN | AVCODES |
| 8677 | MTO | Marathon Airlines | IATA: O8, Callsign: Marathon, | GR | AVCODES |
| 8678 | MTO | Manitoulin Air Services | | | ICAO1 |
| 8679 | MTOB | MARTIN TRANSPORTATION SERVICES INC | | | SCAC4 |
| 8680 | MTOD | MASON TRANSPORTATION CO | | | SCAC4 |
| 8681 | MTOE | M/T TRANSPORTATION INC | | | SCAC4 |
| 8682 | MTOG | MAXIMUS TRANSPORTATION AND LOGISTIC | | | SCAC4 |
| 8683 | MTOH | MIREAULT TRANSPORT | | | SCAC4 |
| 8684 | MTOM | MELTON TRANSPORTATION, INC | | | SCAC1 |
| 8685 | MTOM | MUNOZ TRUCKING | | | SCAC4 |
| 8686 | MTON | MCNAMARA TRUCKING LLC | | | SCAC4 |
| 8687 | MTOO | METALICO TRANSPORT INC | | | SCAC4 |
| 8688 | MTOP | MATHISEN OIL CO INC | | | SCAC4 |
| 8689 | MTOR | MOTORWAYS TRANSPORT LTD | | | SCAC4 |
| 8690 | MTOU | TPS RENTAL SYSTEMS LIMITED | | GB | BIC |
| 8691 | MTOU | METANO CONTAINER LTD | | | SCAC4 |
| 8692 | MTOY | METRO TRUCKING OF ATLANTA LLC | | | SCAC4 |
| 8693 | MTP | Island Helicopters, Inc. | Callsign: Metrocopter, | USA | AVCODES |
| 8694 | MTP | Island Helicopters | | | ICAO1 |
| 8695 | MTP | MIDWEST COACHES INC | | | SCAC4 |
| 8696 | MTPC | M T C TRANSPORTATION CO | | | SCAC4 |
| 8697 | MTPD | MOUNTAIN TRANSPORT INC | | | SCAC4 |
| 8698 | MTPE | M C TRANSPORT ET FILS INC | | | SCAC4 |
| 8699 | MTPF | METROPOLITAN TRANSIT AUTHORITY | | | SCAC4 |
| 8700 | MTPH | MOORE TRANSPORTATION INC | | | SCAC4 |
