| 1 | NX | Air Macau Company Limited | ICAO: AMU, Callsign: Air Macau, IATA Prefix: 675, | MAC | AVCODES |
| 2 | NX | Nationair Canada | ICAO: NXA, Callsign: Nation Airways, Ceased operation | CDN | AVCODES |
| 3 | NX | Air Niagara | | CDN | AVCODES |
| 4 | NX | Fruit Growers Express Co. | added 1/1972; 1/1975-1/1980; eliminated 4/1982 | | NAKINA |
| 5 | NX | National Car Co. | eliminated 1/1972 | | NAKINA |
| 6 | NX | Fruit Growers Express Co. | 7/1937-4/1970 | | NAKINA |
| 7 | NX | National Car Co. | 7/1930-7/1935 | | NAKINA |
| 8 | NX | National Car Co. | Apr-38 | | NRHS |
| 9 | NX | Fruit Growers Express Co. | 1/52-7/65 | | NRHS |
| 10 | NX | National Car Co. | Oct-66 | | NRHS |
| 11 | NX | Fruit Growers Express Co. | Apr-70 | | NRHS |
| 12 | NX | National Car Co. | eliminated 1/72 | | NRHS |
| 13 | NX | Fruit Growers Express Co. | added 1/72; 1/75-1/80; eliminated 4/82 | | NRHS |
| 14 | NX | *MATHIESON DRY ICE | | | PWRC |
| 15 | NX | *NATIONAL CAR CO. (FRUIT GROWERS EXPRESS0 | | | PWRC |
| 16 | NX | Mathieson Dry Ice | | | RSRV |
| 17 | NX | National Car Co. | | USA | TRAFFIC |
| 18 | NX | National Express | | UK | VKM |
| 19 | NXA | Nationair Canada | IATA: NX, Callsign: Nation Airways, Ceased operation | CDN | AVCODES |
| 20 | NXA | Air Next Co. Ltd. | IATA: 7A, Callsign: Blue-Dolphin, Merged with Air Central and Air Nippon Network to form ANA Wings w.e.f. 01 October 2010. | J | AVCODES |
| 21 | NXA | NXT Air Limited | Callsign: Next Air, | BD | AVCODES |
| 22 | NXA | Air Next | | | ICAO1 |
| 23 | NXCC | NEXUS CARRIER CORPORATION | | | SCAC3 |
| 24 | NXCC | NEW MALWA EXPRESS INC | | | SCAC4 |
| 25 | NXCL | NEXUS CARRIERS LLC | | | SCAC4 |
| 26 | NXCOV | National Express Coventry | | GB | TRAFFIC |
| 27 | NXCT | NATIONAL EXPORT CRATING COMPANY OF | | | SCAC3 |
| 28 | NXCU | NIPPON EXPRESS（SHANGHAI）CO., LTD. | | PRC | BIC |
| 29 | NXEA | NORTHLAND EXCHANGE INC | | | SCAC4 |
| 30 | NXEA | National Express East Anglia | | GB | TRAFFIC |
| 31 | NXEC | National Express East Coast | | GB | TRAFFIC |
| 32 | NXEI | NX ENTERPRISES INC | | | SCAC4 |
| 33 | NXF | Nextflight Aviation | Callsign: Nextflight, | USA | AVCODES |
| 34 | NXF | Nextflight Aviation | | | ICAO1 |
| 35 | NXG | National Express Rail GmbH | | DE | VKM |
| 36 | NXGN | NEXGEN ENERGY LLC | | | SCAC4 |
| 37 | NXID | NETRO TRANSPORT INCORPORATED | | | SCAC4 |
| 38 | NXIN | NORTHEAST TRANSPORT INC | | | SCAC4 |
| 39 | NXLZ | NATIONAL XPRESS LOGISTICS INCORPORATED | | | PWRC |
| 40 | NXLZ | National Xpress Logistics | | | RSRV |
| 41 | NXLZ | NATIONAL XPRESS LOGISTICS, INC. | | | SCAC4 |
| 42 | NXN | Nexton, S.A. de C.V. | Callsign: Nexton, | MEX | AVCODES |
| 43 | NXNI | NEXTRANS INCORPORATED | | | SCAC4 |
| 44 | NXNW | NEXANS NORWAY A S | | | SCAC4 |
| 45 | NXON | NIXON TRUCKING, INC | | | SCAC3 |
| 46 | NXOS | NAXOS SHIPPING CO LTD | | | SCAC3 |
| 47 | NXOS | N E X | | | SCAC4 |
| 48 | NXPE | NERCH XPRESS | | | SCAC4 |
| 49 | NXPI | NATIONAL EXPRESS INC | | | SCAC3 |
| 50 | NXPL | National Xpress Logistics | | | SCAC2 |
| 51 | NXPL | NATIONAL XPRESS LOGISTICS | | | SCAC4 |
| 52 | NXPR | NORTHERN EXPRESS | | | SCAC3 |
| 53 | NXPR | NANIX EXPRESS INC | | | SCAC4 |
| 54 | NXPW | NEWPORT EXPRESS WORLDWIDE SERVICES | | | SCAC4 |
| 55 | NXRX | NATIONAL SUGAR REFINING CO THE | | | SCAC3 |
| 56 | NXS | Nexus Aviation Limited | Callsign: Nexus Aviation, AOC Suspended during 2003 by the Nigerian Civil Aviation Authority (NCAA). | WAN | AVCODES |
| 57 | NXS | Nexus Aviation | | | ICAO1 |
| 58 | NXSS | NSS XPRESS INC | | | SCAC4 |
| 59 | NXSU | NEXTER SYSTEMS | | F | BIC |
| 60 | NXT | Texas Air Charters, Inc. d/b/a National Express | Callsign: National Freight, | USA | AVCODES |
| 61 | NXT | NextNet | Callsign: NextNet, | USA | AVCODES |
| 62 | NXT | National Express | | | ICAO1 |
| 63 | NXTG | NIX, CHARLIE TRUCKING | | | SCAC3 |
| 64 | NXTK | NOXIN TRUCKING LLC | | | SCAC4 |
| 65 | NXTL | NEXT LEVEL TRUCKING | | | SCAC4 |
| 66 | NXTS | NEXTRANS | | | SCAC4 |
| 67 | NXTU | NEXTER MUNITIONS | | F | BIC |
| 68 | NXU | Nexus Flight Operations Services | Callsign: Nexus, | SA | AVCODES |
| 69 | NXUS | NEXUS INTERNATIONAL EXPRESS INC. | | | SCAC3 |
