| 3001 | NIEG | NIELSEN SHIPPING LTD. | | | SCAC3 |
| 3002 | NIEG | NINE ONE FOUR SEVEN-EIGHT ZERO FIVE | | | SCAC4 |
| 3003 | NIEJ | NIELSEN, JIM DELIVERY LTD | | | SCAC3 |
| 3004 | NIEL | NIELSEN OIL CO INC | | | SCAC4 |
| 3005 | NIEN | NIENEIER BROS INC | | | SCAC3 |
| 3006 | NIEO | NIETO AND SONS TRUCKING, INC | | | SCAC3 |
| 3007 | NIEP | NATIONAL INDUSTRIES EMBROIDERY PLUS | | | SCAC4 |
| 3008 | NIEP | Omnibusbetrieb Nieporte GmbH | | D | TRAFFIC |
| 3009 | NIER | NIER-MAY TRANSPORTATION INC | | | SCAC3 |
| 3010 | NIES | NIESEN TRUCK LINE | | | SCAC3 |
| 3011 | NIET | NIELSEN, VERN TRUCKING | | | SCAC3 |
| 3012 | NIEV | NIEVES CARTAGE | | | SCAC3 |
| 3013 | NIEW | NICE, ELWYN TRUCKING INC | | | SCAC3 |
| 3014 | NIFB | NINE ONE FOUR ZERO-ONE TWO EIGHT ON | | | SCAC4 |
| 3015 | NIFC | NINE ZERO SIX EIGHT-FIVE EIGHT ONE | | | SCAC4 |
| 3016 | NIFD | NINA INTERNATIONAL FOOD | | | SCAC4 |
| 3017 | NIFF | NAVTRANS INTERNATIONAL FREIGHT FORW | | | SCAC3 |
| 3018 | NIFS | NIGHTHAWK FRT SERV INC | | | PWRC |
| 3019 | NIFS | NICHOLS FLUID SERVICE INC | | | SCAC3 |
| 3020 | NIFS | NINE ZERO FIVE NINE FIVE SIX THREE | | | SCAC4 |
| 3021 | NIFX | General Electric Rail Services Corp. | added 1/2000; 7/2000-7/2005 | | NAKINA |
| 3022 | NIFX | General Electric Railcar Services Corp. | added 1/1984; 1/1994; eliminated 1/2000 | | NAKINA |
| 3023 | NIFX | North American Car Corp. | added 4/1960; 4/1961-1/1980; eliminated 1/1984 | | NAKINA |
| 3024 | NIFX | North American Car Corp. | 4/61-1/80 | | NRHS |
| 3025 | NIFX | General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | | NRHS |
| 3026 | NIFX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 3027 | NIFX | (NATX) GENERAL ELECTRIC RAIL SERVICES CORP. [NORTH AMERICAN CAR CORP.] | | | PWRC |
| 3028 | NIFX | GE Rail Services | | | RSRV |
| 3029 | NIFX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 3030 | NIG | Aero Contractors Company of Nigeria Ltd. | IATA: NU, Callsign: Aeroline, IATA Designator changed to AJ | WAN | AVCODES |
| 3031 | NIG | Aero Contractors Company of Nigeria Ltd. | IATA: AJ, Callsign: Aeroline, Name changed to Aero Contractors Nigeria Limited. IATA Designator changed from NU* | WAN | AVCODES |
| 3032 | NIG | Aero Contractors Nigeria Limited | IATA: AJ, Callsign: Aeroline, IATA Prefix: 914, Name changed from Aero Contractors Company of Nigeria Ltd. IATA Designator changed from NU* | WAN | AVCODES |
| 3033 | NIG | Aero Contractors Nigeria Limited | IATA: NG, Callsign: Aeroline, Ceased operations on 01 September 2016. Name changed from Aero Contractors Company of Nigeria Ltd. IATA Designator changed from NU* | WAN | AVCODES |
| 3034 | NIG | Aero Contractors Company of Nigeria Ltd. | IATA: N2, Callsign: Aeroline, | WAN | AVCODES |
| 3035 | NIG | Aero Contractors | IATA: AJ | | ICAO1 |
| 3036 | NIGA | Niishikigawa Railway | | J | TRAFFIC |
| 3037 | NIGH | NIGHTHAWK DELIVERY SYSTEMS INC | | | SCAC3 |
| 3038 | NIGH | NIGHTHAWK LIMITED | | | SCAC4 |
| 3039 | NIGT | NIGHT TRUCKING LTD | | | SCAC3 |
| 3040 | NIGX | North American Car Corp. | added 10/1961; 7/1965-1/1975; eliminated 10/1979 | | NAKINA |
| 3041 | NIGX | North American Car Corp. | 7/65-1/75 | | NRHS |
| 3042 | NIGX | NORTH AMERICAN CAR CORP. | | | PWRC |
| 3043 | NIH | Nippon Airship Corporation | | J | AVCODES |
| 3044 | NIHH | NICHOLS HEAVY HAULING | | | SCAC3 |
| 3045 | NIHL | NICHOLS, A T TRUCKING CO INC | | | SCAC3 |
| 3046 | NIHON | Nihon Kotsu Co. | | J | TRAFFIC |
| 3047 | NIHW | NITEHAWK EXPRESS INC | | | SCAC3 |
| 3048 | NIHX | General Electric Rail Services Corp. | added 1/2000; 7/2000-7/2005 | | NAKINA |
| 3049 | NIHX | General Electric Railcar Services Corp. | added 1/1984; 1/1994; eliminated 1/2000 | | NAKINA |
| 3050 | NIHX | North American Car Corp. | added 4/1960; 4/1961-1/1980; eliminated 1/1984 | | NAKINA |
| 3051 | NIHX | North American Car Corp. | 4/61-1/80 | | NRHS |
| 3052 | NIHX | General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | | NRHS |
| 3053 | NIHX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 3054 | NIHX | (NATX) GENERAL ELECTRIC RAIL SERVICES CORP. [NORTH AMERICAN CAR CORP.] | | | PWRC |
| 3055 | NIHX | GE Rail Services | | | RSRV |
| 3056 | NIHX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 3057 | NII | ATP NIIS, State Aircompany | Callsign: Niis-Avia, | RUS | AVCODES |
| 3058 | NIIC | NORTON INTERNATIONAL INC | | | SCAC3 |
| 3059 | NIIN | NYIKOS, | | | SCAC4 |
| 3060 | NIJF | NIJ FREIGHT INC | | | SCAC4 |
| 3061 | NIK | Niko Air Ltd. | Callsign: Nik Air, Ceased Operations. | BG | AVCODES |
| 3062 | NIKC | NICKEL CITY TRANSPORT & LEASING COM | | | SCAC3 |
| 3063 | NIKE | NIKE MESSENGER SERVICE INC | | | SCAC3 |
| 3064 | NIKI | NIKI NAVIGATION | | | SCAC3 |
| 3065 | NIKK | NIKOS TRANSPORT & STORAGE INC | | | SCAC4 |
| 3066 | NIKL | NICKELLS VAN & STORAGE INC | | | SCAC3 |
| 3067 | NIKM | NIKO MARITIME INC PIRAEUS GREECE | | | SCAC3 |
| 3068 | NIKS | NIK TRANSPORT INC | | | SCAC4 |
| 3069 | NIKU | NORILSK FORWARDING COMPANY LTD | | RUS | BIC |
| 3070 | NIKX | N.I.K. Non-Stock Marketing Cooperative | added 1/1991; eliminated 7/1993; 1/1994-7/2005 (not listed) | | NAKINA |
| 3071 | NIKX | N.I.K. Non-Stock Marketing Cooperative | added 1/91; eliminated 7/93; 1/94-7/2000 | | NRHS |
| 3072 | NIKX | N.I.K. NON-STOCK MARKETING COOPERATIVE | | | PWRC |
| 3073 | NIKX | NIK Non-stock Marketing Cooperative | | | RSRV |
| 3074 | NIKX | N I K NON | | | SCAC4 |
| 3075 | NILB | NILBORK INVESTMENTS INC | | | SCAC3 |
| 3076 | NILB | NILBORK INVESTMENTS INC | | | SCAC4 |
| 3077 | NILD | NORTHERN ILLINOIS DELIVERY SYSTEMS | | | SCAC3 |
| 3078 | NILG | Nilgiri Rack Railway | | IND | TRAFFIC |
| 3079 | NILM | NICOLES LIMOUSINE SERVICE INC | | | SCAC3 |
| 3080 | NILN | NIELSEN & NEILSEN INC | | | SCAC3 |
| 3081 | NILQ | NILES DELIVERY SERVICE | | | SCAC3 |
| 3082 | NILS | NICOLES TRANSPORTATION INC | | | SCAC3 |
| 3083 | NILT | NORTHERN ILLIONIS TRUCK LINES INC | | | SCAC3 |
| 3084 | NIM | Airnimbus | Callsign: Nimjet, | P | AVCODES |
| 3085 | NIMC | NAPARANO iRON & METAL | | | PWRC |
| 3086 | NIMG | NEW IMAGE TRANSPORTATION INC | | | SCAC3 |
| 3087 | NIMK | NILMEIER, KEITH A | | | SCAC3 |
| 3088 | NIMO | NIMOCKS OIL CO INC | | | SCAC4 |
| 3089 | NIMQ | NEWARK IRON AND METAL CO | | | SCAC3 |
| 3090 | NIMR | NILMEIER, GLENN K | | | SCAC3 |
| 3091 | NIMS | NRC INVESTMENT MEXICO SA DE CV | | | SCAC4 |
| 3092 | NIMT | NORTH IDAHO MOBILE TOWING | | | SCAC3 |
| 3093 | NIMU | RRT RHEIN-RUHR TERMINAL GESELLSCHAFT FUR CONTAINER | | D | BIC |
| 3094 | NIMU | NEW INDIA MARITIME AGENCIES PVT. | | | SCAC3 |
| 3095 | NIMU | RRT RHEIN-RUHR TERMINAL GESELLSCHAF | | | SCAC4 |
| 3096 | NIMX | Naparano/Railroad Division | added 10/1981; eliminated 4/1984 | | NAKINA |
| 3097 | NIMX | Naparano Iron and Metal Co. | added 1/1978; 1/1980; eliminated 10/1981 | | NAKINA |
| 3098 | NIMX | Naparano Iron and Metal Co. | added 1/78; 1/80; eliminated 10/81 | | NRHS |
| 3099 | NIMX | Naparano/Railroad Division | added 10/81; eliminated 4/84 | | NRHS |
| 3100 | NIMX | NAPORANO IRON & METAL, RAILROAD DIV. | | | PWRC |
