| 3501 | NKVT | NKV TRANSPORT | | | SCAC4 |
| 3502 | NKWT | NICKELS, WILLIAM TRUCKING | | | SCAC3 |
| 3503 | NKXP | NK XPRESS | | | SCAC4 |
| 3504 | NKY | Aeromonky, S.A. de C.V. | | MEX | AVCODES |
| 3505 | NKYT | NICKEY TRANSPORTATION LLC | | | SCAC4 |
| 3506 | NKZ | Aerokuzbass, CJSC | Callsign: Novokuznetsk, Name changed to Aerokuzbass Ltd. | RUS | AVCODES |
| 3507 | NKZ | Aerokuzbass Ltd. | Callsign: Novokuznetsk, Name changed from Aerokuzbass, CJSC | RUS | AVCODES |
| 3508 | NKZ | Aerokuzbass | | | ICAO1 |
| 3509 | NL | Shaheen Air International Limited | ICAO: SAI, Callsign: Shaheen Air, IATA Prefix: 740, Established in 1984. Commenced operations in December 1993. Ceased operations on 06 October 2018. | PK | AVCODES |
| 3510 | NL | Lauda Air Italy | ICAO: LDI, IATA designator changed to L4 | I | AVCODES |
| 3511 | NL | Air Liberia | ICAO: ALI, Callsign: November Lima, Designator NL recalled by IATA | LB | AVCODES |
| 3512 | NL | Lierian National Airlines | | LB | AVCODES |
| 3513 | NL | Zapolyarye, Airline Company | ICAO: PZY, Callsign: Zapolyarye, Ceased operations. | RUS | AVCODES |
| 3514 | NL | Aero4M d.o.o. | ICAO: AEH, Callsign: Aerocutter, Name changed to Aero4M d.o.o. d/b/a Amelia International w.e.f. 18 July 2019. | SLO | AVCODES |
| 3515 | NL | Aero4M d.o.o. d/b/a Amelia International | ICAO: AEH, Callsign: Aerocutter, ICAO Callsign changed to Vega. Name changed from Aero4M d.o.o. w.e.f. 18 July 2019. | SLO | AVCODES |
| 3516 | NL | Aero4M d.o.o. d/b/a Amelia International | ICAO: AEH, Callsign: Vega, ICAO Callsign changed from Aerocutter. Name changed from Aero4M d.o.o. w.e.f. 18 July 2019. | SLO | AVCODES |
| 3517 | NL&G | North Louisiana & Gulf R.R. Co. | added 11/1973 | | NAKINA |
| 3518 | NL&G | North Louisiana & Gulf R.R. Co. | added 11/73 | | NRHS |
| 3519 | NL&G | NORTH LOUISIANA & GULF RAILROAD CO. | | | PWRC |
| 3520 | NLA | Peninsula Airways, Inc. t/a PenAir | IATA: KS, Callsign: Peninsula, IATA Prefix: 339, IATA designator KS recalled by IATA. | USA | AVCODES |
| 3521 | NLA | Neiltown Air Ltd. | Callsign: Neiltown Air, | CDN | AVCODES |
| 3522 | NLA | Peninsula Airways, Inc. t/a PenAir | Callsign: Peninsula, IATA designator KS recalled by IATA. | USA | AVCODES |
| 3523 | NLA | Neiltown Air | | | ICAO1 |
| 3524 | NLAD | NIGRO, LOUIS ALEXANDER | | | SCAC4 |
| 3525 | NLAE | NO LIMITS TRUCKING | | | SCAC4 |
| 3526 | NLAF | NLNOVALINK | | | SCAC4 |
| 3527 | NLAN | N-LAND TRANSPORTATION INC | | | SCAC3 |
| 3528 | NLAN | NOLANS FARM EQUIPMENT INC | | | SCAC4 |
| 3529 | NLAS | NELSON A V & SONS | | | SCAC3 |
| 3530 | NLAT | NEAL, AUSTIN TRUCKING | | | SCAC3 |
| 3531 | NLAT | NYK LOGISTICS AMERICAS-TRANSPORTATI | | | SCAC4 |
| 3532 | NLAU | NRS LOGISTICS AMERICA INC. | | USA | BIC |
| 3533 | NLAX | National Aeronautics and Space Administration | added 4/1966; 10/1966-4/1970; eliminated 10/1974; added 7/1982; 1/1994-7/2000; eliminated 1/2004; 7/2005 (not listed) | | NAKINA |
| 3534 | NLAX | National Aeronautics and Space Administration | added 4/66; 10/66-4/70; eliminated 10/74; added 7/82; 1/94-7/2000 | | NRHS |
| 3535 | NLAX | NATIONAL AERONAUTICS & SPACE ADM. (NASA) | | | PWRC |
| 3536 | NLAX | National Aeronautics and Space Administration (NASA) | | | RSRV |
| 3537 | NLAX | NATIONAL AERONAUTICS & SPACE | | | SCAC4 |
| 3538 | NLB | Novosibirsk Airlines | IATA: L8, Voluntary Surrender of IATA prefix | RUS | AVCODES |
| 3539 | NLB | NORTHFIELD LINES INC | | | SCAC4 |
| 3540 | NLB | New Lantau Bus | City: Hong Kong | HK | TRAFFIC |
| 3541 | NLB | Verein Neue Landesbahn | | AT | VKM |
| 3542 | NLBA | NATIONAL BAIT INC | | | SCAC4 |
| 3543 | NLBC | N L B CORP | | | SCAC3 |
| 3544 | NLBC | NIELSEN BROS INCORPORATED | | | SCAC4 |
| 3545 | NLBE | NIGHT LIGHTS BY BEBEE LTD | | | SCAC4 |
| 3546 | NLBL | NEW LONDON-BRADLEY LIMOUSINE SERVIC | | | SCAC3 |
| 3547 | NLBP | NATIONAL LUBRICATING PRODUCTS CO | | | SCAC4 |
| 3548 | NLBS | NELSONS BUS SERVICE INC | | | SCAC3 |
| 3549 | NLBU | NEDLLOYD LINES | | | SCAC3 |
| 3550 | NLBU | NEDLLOYD LIJNEN, BV | | | SCAC4 |
| 3551 | NLC | Nelair Charter (PTY) Ltd. | Callsign: Nelair, | ZA | AVCODES |
| 3552 | NLC | Nelair Charters | | | ICAO1 |
| 3553 | NLC | Missouri Pacific System | eliminated 1/1979 | | NAKINA |
| 3554 | NLC | New Orleans and Lower Coast R.R. Co. | 1/1950-10/1966 & 1/1975 | | NAKINA |
| 3555 | NLC | New Orleans and Lower Coast R.R. Co. | 1/52-10/66 & 1/75 | | NRHS |
| 3556 | NLC | Missouri Pacific System | eliminated 1/79 | | NRHS |
| 3557 | NLC | MISSOURI PACIFIC RAILROAD [NEW ORLEANS & LOWER COAST RR] | | | PWRC |
| 3558 | NLCA | NORTH LOUISIANA CRANES LLC | | | SCAC4 |
| 3559 | NLCB | NORTHLAND CHARTER BUS SERVICE | | | SCAC3 |
| 3560 | NLCB | NORTHLAND CHARTER BUS SERVICE | | | SCAC4 |
| 3561 | NLCH | NORTHLAND COACHES | | | SCAC3 |
| 3562 | NLCL | Northern Lands Railway (Neyveli Lignite Corporation Limited) | | | RSRV |
| 3563 | NLCL | NOVA LUMBER CO LTD | | | SCAC3 |
| 3564 | NLCL | NOVA LUMBER CO LTD | | | SCAC4 |
| 3565 | NLCM | NORTHWAY LIGNIN CHEMICAL | | | SCAC4 |
| 3566 | NLCO | N L C TRANSPORT | | | SCAC4 |
| 3567 | NLCQ | NEILL, L., CARTAGE CO. | | | SCAC3 |
| 3568 | NLCQ | NEILL, L CARTAGE COMPANY INC | | | SCAC4 |
| 3569 | NLCR | NATIONAL COURIER | | | SCAC3 |
| 3570 | NLCT | NLC TRANSPORTATION LLC | | | SCAC4 |
| 3571 | NLCU | LVNF NUCLEAR & LOGISTIC CONSULTING | | F | BIC |
| 3572 | NLCV | NAURI LOGISTICS CO LTD | | | SCAC4 |
| 3573 | NLCX | Namarib Ltd. Corp. | 4/1947 | | NAKINA |
| 3574 | NLCX | Namarib Co. | 1/1950-7/1954; eliminated 4/1957 | | NAKINA |
| 3575 | NLCX | Newberry Lumber & Chemical Co. | 1/1945-1/1946 | | NAKINA |
| 3576 | NLCX | Namarib Co. | 1/52; eliminated 4/57 | | NRHS |
| 3577 | NLCX | NAMARIB CO. [NEWBERRY LUMBER & CHEMICAL CO.] | | | PWRC |
| 3578 | NLD | Namakwaland Lugdiens (EDMS) Bpk. | Callsign: November Juliett, | ZA | AVCODES |
| 3579 | NLDC | NORTHLAND CHARTERS INC | | | SCAC3 |
| 3580 | NLDD | NULAID FOODS INC | | | SCAC3 |
| 3581 | NLDL | NORTHLAND LEASING CO INC | | | SCAC3 |
| 3582 | NLDO | NOLTE, DON | | | SCAC3 |
| 3583 | NLDS | NORTHLAND TRANSPORTATION SERVICES I | | | SCAC3 |
| 3584 | NLDT | NORTHLAND TRAVEL | | | SCAC3 |
| 3585 | NLDU | TDG EUROPEAN CHEMICALS | | | SCAC4 |
| 3586 | NLDY | NORTHERN LIGHTS DAIRY | | | SCAC4 |
| 3587 | NLDZ | NORTHLAND TRUCKING INC | | | SCAC4 |
| 3588 | NLE | Northern Air Services | Callsign: Northern, | ZA | AVCODES |
| 3589 | NLE | Boston-Maine Airways d/b/a FAA William J. Hughes Technical Center Shuttle | Callsign: Nellie, | USA | AVCODES |
| 3590 | NLE | National Airlines | Callsign: Silver Streak, | USA | AVCODES |
| 3591 | NLE | Niederlausitzer Eisenbahn | | D | TRAFFIC |
| 3592 | NLEA | NATIONAL LTL EXPRESS CORP | | | SCAC4 |
| 3593 | NLEC | NATIONAL LEASE CORP | | | SCAC3 |
| 3594 | NLEI | NELSON EXPRESS INC | | | SCAC3 |
| 3595 | NLEN | NILSON CO | | | SCAC3 |
| 3596 | NLEP | NOEL EXPRESS | | | SCAC3 |
| 3597 | NLEP | NORTHERN LIGHTS EXPEDITIONS LTD | | | SCAC4 |
| 3598 | NLEQ | NATIONAL EQUIPMENT SERVICES L C | | | SCAC4 |
| 3599 | NLER | NELSON, LEROY | | | SCAC4 |
| 3600 | NLET | NELSON EXCAVATING AND TRUCKING | | | SCAC3 |
