| 1 | KJ | British Mediterranean Airways Limited | ICAO: LAJ, Callsign: Bee Med, IATA Prefix: 436, Name changed to British Mediterranean Airways Limited t/a Bmed | GB | AVCODES |
| 2 | KJ | Aerodienst GmbH | Callsign: Aerodienst, | D | AVCODES |
| 3 | KJ | Sultan Air | ICAO: SUT, Callsign: Sultan, Ceased operations | TR | AVCODES |
| 4 | KJ | Air Swift Aviation (PTY) Ltd. | ICAO: JOA, Designator KJ recalled by IATA | AUS | AVCODES |
| 5 | KJ | Crescent Air Transport Ltd. | Callsign: Crescent, | PK | AVCODES |
| 6 | KJ | Netherlands Airlines for European Commuter Services (Netherlands) | ICAO: NET, Callsign: Netherlines, IATA Desigantor changed to WU | NL | AVCODES |
| 7 | KJ | British Mediterranean Airways Limited t/a Bmed | ICAO: LAJ, Callsign: Bee Med, IATA Prefix: 436, Merged in bmi. Name changed from British Mediterranean Airways Limited | GB | AVCODES |
| 8 | KJ | Asian Air | ICAO: AAZ, Callsign: Aibek Airways, IATA Prefix: 666, AOC suspended on 07 February 2016. | KS | AVCODES |
| 9 | KJ | Air Incheon Co., Ltd. | ICAO: AIH, Callsign: Air Incheon, | ROK | AVCODES |
| 10 | KJ | Kalmar Järnväg | 1874 - 1940 | S | svenska-lok.se |
| 11 | KJA | Avistar (Cyprus) Limited | Callsign: Aviastar, | CY | AVCODES |
| 12 | KJA | Kinda Airlines | IATA: 2S, Callsign: Kinda, IATA Prefix: 338, Never commenced operations. | SYR | AVCODES |
| 13 | KJAB | KLIPPENSTEIN, JACOB | | | SCAC4 |
| 14 | KJAI | KRAFT, JOHN A FERTILIZER INC | | | SCAC3 |
| 15 | KJAM | KARSTEN, JAMES TRUCKING | | | SCAC3 |
| 16 | KJAM | K & J TRUCKING INC | | | SCAC4 |
| 17 | KJAP | KJ ALPACAS | | | SCAC4 |
| 18 | KJAS | KEY, JACK AUTO SALES | | | SCAC3 |
| 19 | KJAT | KING JAMES AUTO TRANSPORT INC | | | SCAC3 |
| 20 | KJB | Kaiser Jamaica Bauxite Co. | | JA | TRAFFIC |
| 21 | KjBJ | Kävlinge - Barsebäck Järnväg | 1907 - 1927 | S | svenska-lok.se |
| 22 | KJBT | KJB TRANSPORTATION COMPANY INC | | | SCAC3 |
| 23 | KJC | Krasnoyarsk Airlines d/b/a KrasAir Airlines | IATA: 7B, Callsign: Krasnojarsky Air, IATA Prefix: 499, Founded in 1993. Ceased operations on 01 November 2008. | RUS | AVCODES |
| 24 | KJC | Krasnojarsky Airlines | IATA: 7B | | ICAO1 |
| 25 | KJCN | KELLY, J C INC | | | SCAC3 |
| 26 | KJCU | ZEBULUN CONTAINERS PTE LTD | | SGP | BIC |
| 27 | KJD | Forces Aeriennes Algeriennes | Callsign: Algerian Airforce, | DZ | AVCODES |
| 28 | KJDT | KENDALL, JOHN D TRUCKING | | | SCAC3 |
| 29 | KJE | Kapajet S.A. | Callsign: Kapajet, | GR | AVCODES |
| 30 | KJEC | KNOX, JAMES E CONTRACT TRUCKING | | | SCAC3 |
| 31 | KJET | K J TRANSPORTATION INC | | | SCAC3 |
| 32 | KJET | K J TRANSPORTATION INC | | | SCAC4 |
| 33 | KJFA | KEAY, JIM FORD LINCOLN SALES LTD | | | SCAC4 |
| 34 | KJFJ | KENNEDY, JEROME FRANCIS JR | | | SCAC3 |
| 35 | KJFT | KJF TRUCKING INC | | | SCAC4 |
| 36 | KJGC | K.J.G. CARTAGE, INC | | | SCAC3 |
| 37 | KJGC | K J G CARTAGE INC | | | SCAC4 |
| 38 | KJHL | KELLER, JOHN L | | | SCAC3 |
| 39 | KJHS | KJORSTAD HOT SHOT | | | SCAC4 |
| 40 | KJIC | KRAM-J INC | | | SCAC4 |
| 41 | KJLC | KELLY, J L CO | | | SCAC3 |
| 42 | KJLG | K J LEASING | | | SCAC3 |
| 43 | KJLK | KROPP, J L TRUCKING INC | | | SCAC4 |
| 44 | KJMS | KENNELLY JOSEPH MOVING AND STORAGE | | | SCAC3 |
| 45 | KJOE | KILAMANJARO ENTERPRISES LLC | | | SCAC4 |
| 46 | KJOL | KIDD, JERRY OIL CO | | | SCAC4 |
| 47 | KJPP | KIRYAS JOEL POULTRY PROCESSING PLAN | | | SCAC4 |
| 48 | KJPT | K J P INC | | | SCAC3 |
| 49 | KJR | Berkman Rail Services, Inc. d/b/a Kiski Junction R.R. | added 10/1995; eliminated 7/1998; 7/2000-7/2005 | | NAKINA |
| 50 | KJR | Berkman Rail Services, Inc. d/b/a Kiski Junction R.R. | added 10/95; eliminated 7/98; 7/2000 | | NRHS |
| 51 | KJR | BERKMAN RAIL SERVICES INC. d/b/a KISKI JUNCTION RR | | | PWRC |
| 52 | KJR | Kiski Junction Railroad | | | RSRV |
| 53 | KJR | KISKI JUNCTION RAILROAD | | | SCAC4 |
| 54 | KJRT | KJELSHUS, ROBERT | | | SCAC3 |
| 55 | KJRY | Keokuk Junction Ry. | added 4/1982; 1/1994-7/2000; eliminated 10/2001; 7/2005 | | NAKINA |
| 56 | KJRY | Keokuk Northern Real Estate Co. (d/b/a Keokuk Junction Ry.) | added 1/1982; eliminated 4/1982 | | NAKINA |
| 57 | KJRY | Keokuk Northern Real Estate Co. (d/b/a Keokuk Junction Ry.) | added 1/82; eliminated 4/82 | | NRHS |
| 58 | KJRY | Keokuk Junction Ry. | added 4/82; 1/94-7/2000 | | NRHS |
| 59 | KJRY | KEOKUK JUNCTION RAILWAY (KEOKUK NORTHERN REAL ESTATE CO.) | | | PWRC |
| 60 | KJRY | Keokuk Junction Railway | | | RSRV |
| 61 | KJRY | KEOKUK JUNCTION RAILWAY | | | SCAC3 |
| 62 | KJSI | KUHNI, JOHN SONS INC | | | SCAC3 |
| 63 | KJSI | KUHNI, JOHN SONS INC | | | SCAC4 |
| 64 | KJT | Shanghai Kingjet General Aviation Co., Ltd. | Callsign: Shanghai Kingjet, | PRC | AVCODES |
| 65 | KJTD | K J TRANSPORT | | | SCAC4 |
| 66 | KJTF | K J T FLORIDA FRESH EXPRESS | | | SCAC4 |
| 67 | KJTI | KNIGHT, JACK TRUCKING | | | SCAC3 |
| 68 | KJTI | KJS TRUCKING LLC | | | SCAC4 |
| 69 | KJTK | K & J TRUCKING | | | SCAC3 |
| 70 | KJTK | K & J TRUCKING | | | SCAC4 |
| 71 | KJTL | K & J TRANSPORTATION LLC | | | SCAC4 |
| 72 | KJTN | K & J TRUCKING | | | SCAC3 |
| 73 | KJTO | KELLER & JOHNSON TRANSPORT INC | | | SCAC3 |
| 74 | KJTP | K J TRANSPORTATION INC | | | SCAC3 |
| 75 | KJTQ | KING J TRANSPORTATION INC | | | SCAC4 |
| 76 | KJTS | K & J TRANSPORT | | | SCAC4 |
| 77 | KJUN | KAJUN DRIVE SERVICE | | | SCAC3 |
| 78 | KJVR | KIRBY, JACK V & ROBIN | | | SCAC3 |
| 79 | KJWS | KEY, JW EXPRESS | | | SCAC4 |
| 80 | KJXT | KJAX TRUCKING | | | SCAC4 |
| 81 | KJZA | KJZ ASSOCIATES | | | SCAC3 |
