| 2501 | MEFQ | MISSION EXPEDITED FREIGHT INC | | | SCAC4 |
| 2502 | MEFR | METROPOLITAN FREIGHT CARRIERS CORP | | | SCAC4 |
| 2503 | MEFRV | Mota-Engil Ferrovias | | PT | VKM |
| 2504 | MEFS | Mecklenburgische Eisenbahnfreunde Schwerin e.V. | Schwerin | D | privat-bahn.de |
| 2505 | MEFS | MERCURY FUEL SERVICE INC | | | SCAC4 |
| 2506 | MEFV | MERCANTILE FREIGHT SERVICE | | | SCAC4 |
| 2507 | MEFX | MexFresh, L.L.C. | 7/2005 (not listed) | | NAKINA |
| 2508 | MEFX | MEXFRESH, LLC | | | PWRC |
| 2509 | MEFX | MexFresh | | | RSRV |
| 2510 | MEFX | MEXFRESH LLC | | | SCAC4 |
| 2511 | MEFZ | MexFresh | | | RSRV |
| 2512 | MEFZ | MEXFRESH LLC | | | SCAC4 |
| 2513 | MEG | Megamicro RT. | Callsign: Megamicro, | H | AVCODES |
| 2514 | MEG | Mega Airlines | Callsign: Megalines, | AM | AVCODES |
| 2515 | MEG | Mega Global Air Services (Maldives) Pvt. Ltd. t/a MEGA Maldives Airlines | IATA: 5M, Callsign: Sandbar, Founded on 23 February 2010. AOC granted on 22 December 2010. Commenced operations on 23 December 2010. IATA Designator changed to LV | MV | AVCODES |
| 2516 | MEG | Mega Global Air Services (Maldives) Pvt. Ltd. t/a MEGA Maldives Airlines | IATA: LV, Callsign: Sandbar, IATA Prefix: 400, Founded on 23 February 2010. AOC granted on 22 December 2010. Commenced operations on 23 December 2010. Ceased operations on 02 May 2017. IATA Designator changed from 5M | MV | AVCODES |
| 2517 | MEG | Mitteldeutsche Eisenbahn GmbH | Schkopau | D | privat-bahn.de |
| 2518 | MEG | Märkische Eisenbahngesellschaft GmbH | Plettenberg | D | privat-bahn.de |
| 2519 | MEG | Mitteldeutscher Eisenbahngesellschaft GmbH | | D | TRAFFIC |
| 2520 | MEG | Mitteldeutsche Eisenbahn Gesellschaft | | DE | VKM |
| 2521 | MEGA | Megabus | | GB | TRAFFIC |
| 2522 | MEGB | M E LOGISTICS INC | | | SCAC4 |
| 2523 | MEGC | MEGA FLEET LOGISTICS | | | SCAC4 |
| 2524 | MEGF | MEGA FUELS | | | SCAC4 |
| 2525 | MEGG | MEGA CHEMICALS SCHIFFAHRT AG | | | SCAC4 |
| 2526 | MEGH | MEGA TRANSFER INC | | | SCAC4 |
| 2527 | MEGI | MEGA LOGISTICS INC | | | SCAC4 |
| 2528 | MEGJ | MASTER TRANSPORTATION INC | | | SCAC4 |
| 2529 | MEGK | MILLER ENVIRONMENTAL GROUP INC | | | SCAC4 |
| 2530 | MEGO | MEGA TRANSPORTACIONES DEL NORTE SA | | | SCAC4 |
| 2531 | MEGQ | MENINI CARTAGE, INC | | | SCAC1 |
| 2532 | MEGR | MEGA STAR TRADING INC | | | SCAC4 |
| 2533 | MEGU | SHANGHAI MEG IMPORT AND EXPORT CORPORATION | | PRC | BIC |
| 2534 | MEGW | MEGA SUPPLY CHAIN SOLUTIONS INC | | | SCAC4 |
| 2535 | MEGX | MEGLOBAL AMERICAS INC | | | SCAC4 |
| 2536 | MEGY | MAINE ENERGY INC | | | SCAC4 |
| 2537 | MEH | Malev Express Ltd. | Callsign: Greenmalev, | H | AVCODES |
| 2538 | MEH | Museumseisenbahn Hamm | | DE | VKM |
| 2539 | MEHB | MAXTON ECKSTEIN HORSE TRANSPORT | | | SCAC4 |
| 2540 | MEHE | MEHAT TRUCKING LTD | | | SCAC4 |
| 2541 | MEHG | MIKES EQUIPMENT HAULING LLC | | | SCAC4 |
| 2542 | MEHI | MEEHAN | | | SCAC4 |
| 2543 | MEHL | MEHLMAN TRUCKING | | | SCAC4 |
| 2544 | MEI | Merlin Express, Inc. | Callsign: Avalon, Name changed to Merlin Airways, Inc. | USA | AVCODES |
| 2545 | MEI | Merlin Airways, Inc. | Callsign: Avalon, Name changed from Merlin Express, Inc. Fedex-Feeder | USA | AVCODES |
| 2546 | MEI | Merlin Airways | | | ICAO1 |
| 2547 | MEIA | MEIER BROTHERS FARMS | | | SCAC4 |
| 2548 | MEIB | MORKEN EXPRESS INC | | | SCAC4 |
| 2549 | MEID | MNM EMPIRE INC | | | SCAC4 |
| 2550 | MEIDB | Meidenbauer Reiobus | | D | TRAFFIC |
| 2551 | MEIE | MEIER TRUCKING COMPANY, INC. | | | SCAC1 |
| 2552 | MEIG | Mitteldeutsche Eisenbahninfrastrukturgesellschaft mbH | | DE | VKM |
| 2553 | MEIJ | MEIJER LOGISTICS LLC | | | SCAC4 |
| 2554 | MEIK | MARTIN ENTERPRISE INC | | | SCAC4 |
| 2555 | MEIM | MEI MEE LIMITED | | | SCAC4 |
| 2556 | MEIO | MEIER OIL SERVICE INC | | | SCAC4 |
| 2557 | MEIP | MEI EQUIPMENT INC | | | SCAC4 |
| 2558 | MEIR | MECIAS IBARRA, ROGELIO | | | SCAC4 |
| 2559 | MEIS | MEISLER TRAILER RENTALS INC | | | SCAC4 |
| 2560 | MEIU | MESSER ITALIA SPA | | | SCAC4 |
| 2561 | MEIV | MASTERLINE EXPRESS INC | | | SCAC4 |
| 2562 | MEIY | MENES ENTERPRISES INC | | | SCAC4 |
| 2563 | MEJ | Medjet International, Inc. | Callsign: Medjet, Name changed to Airmed International, LLC w.e.f. 21 September 2021. | USA | AVCODES |
| 2564 | MEJ | AirMed International, LLC | Callsign: Medjet, Name changed from Medjet International, Inc. w.e.f 21 September 2021. | USA | AVCODES |
| 2565 | MEJ | Medjet International | | | ICAO1 |
| 2566 | MEJL | MILLER, C J LLC | | | SCAC4 |
| 2567 | MEJR | MARJOE EXPRESS INC | | | SCAC4 |
| 2568 | MEJT | MESA BROTHERS TRUCKING COMPANY INC | | | SCAC4 |
| 2569 | MEK | Med-Trans Of Florida, Inc. | Callsign: Med-Trans, | USA | AVCODES |
| 2570 | MEK | Med-Trans of Florida | | | ICAO1 |
| 2571 | MEK | M. E. K. Mitteldeutsche Elektro- und Kabeltiefbau GmbH | | DE | VKM |
| 2572 | MEKC | MELMARK CARTAGE CO | | | SCAC1 |
| 2573 | MEKD | MARINER TRUCKING | | | SCAC4 |
| 2574 | MEKH | MTECH | | | SCAC4 |
| 2575 | MEKM | MASTERS TRUCKING INC | | | SCAC4 |
| 2576 | MEKO | MESKO SPOTTING SERVICE INC | | | SCAC4 |
| 2577 | MEKQ | MCENTIRE, R C TRUCKING INC | | | SCAC4 |
| 2578 | MEKR | MEADOW LARK TRANSPORT INC | | | SCAC4 |
| 2579 | MEKT | MEEKS, T TRUCKING LLC | | | SCAC4 |
| 2580 | MEKY | MEI TRUCKING COMPANY LLC | | | SCAC4 |
| 2581 | MEL | BAe Civil Division Warton | Callsign: Minstrel, | GB | AVCODES |
| 2582 | MEL | Mega Linhas Aereas | | | ICAO1 |
| 2583 | MEL | Museums-Eisenbahn-Club Losheim | | DE | VKM |
| 2584 | MELA | MELANSON TRANSPORTATION INC | | | SCAC4 |
| 2585 | MELB | MELBURN TRUCK LINES INC | | | SCAC4 |
| 2586 | MELC | MELROSE TRANSPORT SYSTEMS, INC | | | SCAC1 |
| 2587 | MELC | MELROSE TRANSPORT SYSTEMS INC | | | SCAC4 |
| 2588 | MELD | MELHORN, TIM TRUCKING LLC | | | SCAC4 |
| 2589 | MELE | MCGILLS ENT LTD | | | SCAC4 |
| 2590 | MELI | MELCARM INC | | | SCAC4 |
| 2591 | MELJ | MJM EXPRESS LLC | | | SCAC4 |
| 2592 | MELL | MELLOTT TRANSPORT INC | | | SCAC4 |
| 2593 | MELM | M E L MARITIME GMBH | | | SCAC4 |
| 2594 | MELO | MTRANS ENTERPRISES LTD | | | SCAC4 |
| 2595 | MELP | M & E BALTIC TRANSPORTATION LLC | | | SCAC4 |
| 2596 | MELR | MELENDREZ, A TRUCKING | | | SCAC4 |
| 2597 | MELS | MEL & SONS OIL SALES INC | | | SCAC4 |
| 2598 | MELT | MEL & SONS TRUCKING CORP | | | SCAC4 |
| 2599 | MELU | JORN BOLDING A/S | | DK | BIC |
| 2600 | MELU | MESSER GREISHEIM GMBH | | | SCAC4 |
