| 601 | NATX | North American Tank Line (North American Car Co.) | 8/1920-7/1923 | | NAKINA |
| 602 | NATX | North American Tank Line (North American Car Corp.) | Apr-38 | | NRHS |
| 603 | NATX | North American Car Corp. | 1/52-1/80 | | NRHS |
| 604 | NATX | General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | | NRHS |
| 605 | NATX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 606 | NATX | GENERAL ELECTRIC RAIL SERVICES CORP.[NORTH AMERICAN CAR CORP.; NORTH AMERICAN TANK LINE] | | | PWRC |
| 607 | NATX | North American Tank Line (GE Rail Services) | | | RSRV |
| 608 | NATX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 609 | NATX | North Americal Tank Line | | USA | TRAFFIC |
| 610 | NATY | NATIONAL GYPSUM ENERGY COMPANY | | | SCAC4 |
| 611 | NATZ | NORTH AMERICAN TRANSPORTATION | | | PWRC |
| 612 | NATZ | North American Transportation | | | RSRV |
| 613 | NATZ | NORTH AMERICAN TRANSPORTATION | | | SCAC4 |
| 614 | NAU | Antanik-Air | Callsign: Antanik, | UA | AVCODES |
| 615 | NAU | Danaus Lineas Aereas, S.A. de C.V. | Callsign: Danaus, Ceased operations. | MEX | AVCODES |
| 616 | NAU | Antanik-Air | | | ICAO1 |
| 617 | NAUG | Naugatuck R.R. Co., Inc. | 7/2000-7/2005 | | NAKINA |
| 618 | NAUG | Naugatuck R.R. Co., Inc. | Jul-00 | | NRHS |
| 619 | NAUG | NAUGATUCK RAILROAD CO. | | | PWRC |
| 620 | NAUG | Naugatuck Railroad | | | RSRV |
| 621 | NAUG | NAUGATUCK RAILROAD COMPANY INC | | | SCAC4 |
| 622 | NAUK | NORTH ATLANTIC UNITED KINGDOM FREIG | | | SCAC3 |
| 623 | NAUL | NATURAL TRUCK LEASING INC | | | SCAC3 |
| 624 | NAUM | NAUGHTON, MARY | | | SCAC4 |
| 625 | NAUM | | City: Naumburg | D | TRAFFIC |
| 626 | NAUO | NATIONWIDE AUTO TRANSPORT INC | | | SCAC3 |
| 627 | NAUO | NAO AUTO | | | SCAC4 |
| 628 | NAUQ | NATURAL TRANSPORT INC | | | SCAC4 |
| 629 | NAUR | NATURE CALVES LTD | | | SCAC4 |
| 630 | NAUS | NAUTILUIS LINES | | | SCAC3 |
| 631 | NAUT | NATIONAL AUTO TRANSPORT INC | | | SCAC3 |
| 632 | NAV | Nav Flight Planning | Callsign: Nav Dispatch, | CZ | AVCODES |
| 633 | NAV | Nav Flight Planning | | | ICAO1 |
| 634 | NAVA | NAVAJO FREIGHT LINES INC | | | PWRC |
| 635 | NAVA | NAVIERAS NPR, INC. | | | SCAC3 |
| 636 | NAVB | NAVIERA BLANCAMAR S A | | | SCAC4 |
| 637 | NAVC | NORTH AMERICAN VAN LINES INC-COMMER | | | SCAC3 |
| 638 | NAVC | NORTH AMERICAN VAN LINES | | | SCAC4 |
| 639 | NAVE | Navajo Express, Inc. | 7/2000-7/2005 | | NAKINA |
| 640 | NAVE | Navajo Express, Inc. | Jul-00 | | NRHS |
| 641 | NAVE | NAVAJO EXPRESS INCORPORATED | | | PWRC |
| 642 | NAVE | Navajo Express | | | RSRV |
| 643 | NAVE | NAVAJO EXPRESS INC | | | SCAC3 |
| 644 | NAVE | NAVAJO EXPRESS INC | | | SCAC4 |
| 645 | NAVH | NORTH AMERICAN VAN LINES INC-HIGH V | | | SCAC3 |
| 646 | NAVI | NORTH AMERICAN VAN LINES INC-INTERN | | | SCAC3 |
| 647 | NAVI | NORTH AMERICAN VAN LINES INC-INTERN | | | SCAC4 |
| 648 | NAVI | NAVILAND CARGO | | FR | VKM |
| 649 | NAVJ | NAVAJO SHIPPERS INC | | | SCAC3 |
| 650 | NAVJ | NAVAJO SHIPPERS INC | | | SCAC4 |
| 651 | NAVL | NATIONAL VAN LINES, INC. | | | SCAC3 |
| 652 | NAVL | NATIONAL VAN LINES INC | | | SCAC4 |
| 653 | NAVN | NORTH AMERICAN VAN LINES INC-AIR FR | | | SCAC3 |
| 654 | NAVN | NORTH AMERICAN VAN LINES INC-AIR FR | | | SCAC4 |
| 655 | NAVO | NAVAJO TRIBAL UTILITY AUTHORITY | | | SCAC3 |
| 656 | NAVO | NAVIOS INTERNATIONAL INC | | | SCAC4 |
| 657 | NAVP | NAVIROUTE | | | SCAC4 |
| 658 | NAVR | NAVINTER, MAPUTO MOZAMBIQUE | | | SCAC3 |
| 659 | NAVR | NAVARROS TRUCKING | | | SCAC4 |
| 660 | NAVS | NAVALANY & SON | | | SCAC3 |
| 661 | NAVS | NAVALANY & SON | | | SCAC4 |
| 662 | NAVT | NAVA TRUCKING | | | SCAC3 |
| 663 | NAVU | NAVIS CAR LINE PTE .LTD. | | SGP | BIC |
| 664 | NAVU | NAVIERA INTERAMERICANA NAVICANA S A | | | SCAC3 |
| 665 | NAVU | NAVIERA INTERAMERICANA NAVICANA S.A | | | SCAC4 |
| 666 | NAVY | NAVY, L J TRUCKING CO | | | SCAC3 |
| 667 | NAVY | NAVY, L J TRUCKING CO | | | SCAC4 |
| 668 | NAW | Nass LLC | | RUS | AVCODES |
| 669 | NAW | Newair A/S | IATA: 8L, Callsign: Newdan, Designator 8L* recalled by IATA | DK | AVCODES |
| 670 | NAWD | NATIONWIDE TRANSPORT SERVICES INC | | | SCAC4 |
| 671 | NAWE | NATIONWIDE EXPRESS INC | | | SCAC3 |
| 672 | NAWF | NORTH ATLANTIC WESTBOUND FREIGHT AS | | | SCAC3 |
| 673 | NAWH | NATIONAL WAREHOUSE & DISTRIBUTION C | | | SCAC3 |
| 674 | NAWI | NATIONWIDE TRANSPORT SERVICES INC | | | SCAC4 |
| 675 | NAWL | NAPLES AUTO WHOLESALE LLC | | | SCAC4 |
| 676 | NAWR | NACON WRECKER SERVICE | | | SCAC3 |
| 677 | NAWS | NATIONAL WRECKER SERVICE | | | SCAC3 |
| 678 | NAWT | NATIONWIDE TRANSPORTATION SERVICE I | | | SCAC3 |
| 679 | NAWU | NORTH AMERICAN WEST AFRICAN LINE | | | SCAC3 |
| 680 | NAWU | NORTH AMERICAN WEST AFRICAN LINE | | | SCAC4 |
| 681 | NAX | Norwegian Air Shuttle A.S. t/a Norwegian | IATA: DY, Callsign: Nor Shuttle, IATA Prefix: 328, IATA designator changed from N8. IATA designator changed to DY. | N | AVCODES |
| 682 | NAX | Norwegian Air Shuttle A.S. | IATA: N8, Callsign: Nor Shuttle, Designator N8 recalled by IATA | N | AVCODES |
| 683 | NAX | A.S. Air-X | Callsign: Scanbird, | FIN | AVCODES |
| 684 | NAX | Norwegian Air Shuttle A.S. t/a Norwegian | IATA: DY, Callsign: Nor Shuttle, IATA Prefix: 328, IATA designator changed from DY*. IATA designator previously changed from N8. | N | AVCODES |
| 685 | NAX | Norwegian Air Shuttle | IATA: DY | | ICAO1 |
| 686 | NAX | National Ammonia Co., Inc. | 7/1930 | | NAKINA |
| 687 | NAX | National Ammonia Co. | 7/1923 | | NAKINA |
| 688 | NAX | The National Ammonia Co. | 8/1920 | | NAKINA |
| 689 | NAX | NATIONAL AMMONIA CO. | | | PWRC |
| 690 | NAXA | NINTH AFRAMAX TANKER CORPORATION | | | SCAC4 |
| 691 | NAXE | NACO EXPRESS | | | SCAC4 |
| 692 | NAXI | N A TRANSPORT INC | | | SCAC4 |
| 693 | NAXL | NORTH AMEX LOGISTICS INC | | | SCAC4 |
| 694 | NAXO | NATIONAL AUTO TRANSPORT | | | SCAC4 |
| 695 | NAXP | NORTH ALABAMA EXPRESS, INC | | | SCAC3 |
| 696 | NAXP | NAPOLEON EXPRESS SA DE CV | | | SCAC4 |
| 697 | NAXQ | NEW AMERICA TRANSPORTATION INC | | | SCAC4 |
| 698 | NAXS | N A T S | | | SCAC4 |
| 699 | NAXT | N AMERIX TRAFFIC INC | | | SCAC3 |
| 700 | NAXU | NAPHTACHIMIE | | | SCAC3 |
