| 1 | KK | Air Star Corporation | ICAO: ASC, Callsign: Air Star, | CDN | AVCODES |
| 2 | KK | Transportes Aereos Regionais S.A. (TAM) | ICAO: TAM, Callsign: TAM, Name changed to TAM - Linhas Aerea S.A. | BR | AVCODES |
| 3 | KK | Transmeridian Air Cargo Ltd. | Callsign: Transmeridan, Merged into British Cargo Airlines in 1979 | GB | AVCODES |
| 4 | KK | Arab International Aviation Company | Callsign: Arabia, | ET | AVCODES |
| 5 | KK | Atlasjet Uuslararasi Havacilik A/S | ICAO: OGE, Callsign: Atlasjet, ICAO designator changed to KKK . IATA designator changed from 2U*. Name changed from Atlas International Airlines - Atlas International Havacilik A/S | TR | AVCODES |
| 6 | KK | Atlasjet Uuslararasi Havacilik A/S | ICAO: KKK, Callsign: Atlasjet, IATA Prefix: 610, ICAO designator changed from OGE . IATA designator changed from 2U*. Name changed from Atlas International Airlines - Atlas International Havacilik A/S | TR | AVCODES |
| 7 | KK | Atlasjet Airlines Inc | ICAO: KKK, Callsign: Atlasjet, IATA Prefix: 610, Name changed to AtlasGlobal Airlines. Name changed from Atlas International Airlines - Atlas International Havacilik A/S. ICAO designator changed from OGE . IATA designator changed from 2U* | TR | AVCODES |
| 8 | KK | AtlasGlobal Airlines | ICAO: KKK, Callsign: Atlasjet, IATA Prefix: 610, Ceased operations on 12 February 2020. Name changed from Atlasjet Airlines Inc. Name changed from Atlas International Airlines - Atlas International Havacilik A/S. ICAO designator changed from OGE . IATA designator changed from 2U* | TR | AVCODES |
| 9 | KK | LEAV Aviation GmbH | ICAO: NGN, Callsign: Yoda, Name changed from JOOT Aviation Project GmbH. | D | AVCODES |
| 10 | KK | K&K - Eisenbahn-, Speise- und Salonwagen GmbH | | D | TRAFFIC |
| 11 | KKA | Kazavia | Callsign: Kakaair, | KZ | AVCODES |
| 12 | KKA | Kazavia | | | ICAO1 |
| 13 | KKAH | KOLD KATCHER | | | SCAC4 |
| 14 | KKAR | KELLEYS KARTAGE & EXPEDITING SERVIC | | | SCAC3 |
| 15 | KKAT | K K & T INC | | | SCAC3 |
| 16 | KKAT | K K & T INC | | | SCAC4 |
| 17 | KKAW | KOYO KAIUN CO LTD | | | SCAC4 |
| 18 | KKB | Air South, Inc. | Callsign: Khaki Blue, | USA | AVCODES |
| 19 | KKB | Air South, Inc. | IATA: WV, | USA | AVCODES |
| 20 | KKB | Air South | | | ICAO1 |
| 21 | KKB | KKB s.r.o. | | CZ | VKM |
| 22 | KKBC | K & K BROKERAGE LLC | | | SCAC4 |
| 23 | KKBL | K & K BUS LINE | | | SCAC3 |
| 24 | KKBU | KERNKRAFTWERK BRUNSBUTTEL GMBH & CO. OHG | | D | BIC |
| 25 | KKCA | K K CARRIERS | | | SCAC4 |
| 26 | KKCB | KLENKE CHARTER BUS SERVICE | | | SCAC3 |
| 27 | KKCB | KILLORAN TRUCKING | | | SCAC4 |
| 28 | KKCE | KKC EXPRESS CORP | | | SCAC4 |
| 29 | KKCI | KOOLKAT CARRIERS INC | | | SCAC4 |
| 30 | KKCL | KAMBARA KISEN CO., LTD. | | | SCAC3 |
| 31 | KKCO | KELLY KONSOLIDATING COMPANY INC | | | SCAC3 |
| 32 | KKCO | KURTS TRUCKING | | | SCAC4 |
| 33 | KKCQ | KAISER KARTAGE CO | | | SCAC3 |
| 34 | KKCR | KIRK CARRIERS LLC | | | SCAC4 |
| 35 | KKCS | KENTS KORNER CONVENIENCE STORES | | | SCAC4 |
| 36 | KKCW | KAMBARA KISEN CO LTD | | | SCAC4 |
| 37 | KKCX | Glaser, Crandell Co. | 1/1946 (not listed) | | NAKINA |
| 38 | KKCX | Keokuk Canning Co. | 7/1935-1/1945 | | NAKINA |
| 39 | KKCX | Keokuk Canning Co. | Apr-38 | | NRHS |
| 40 | KKCX | GLASER, CRANDELL CO. [KEOKUK CANNING CO.] | | | PWRC |
| 41 | KKDE | KKD ENTERPRISES INC | | | SCAC3 |
| 42 | KKDH | KRZESKI, K D HORSE TRANSPORTATION | | | SCAC3 |
| 43 | KKDI | K & K DISTRIBUTION | | | SCAC3 |
| 44 | KKES | KELLEY KARTAGE & EXPEDITING SERVICE | | | SCAC3 |
| 45 | KKET | K & K ENTERPRISES AND TRUCKING LLC | | | SCAC4 |
| 46 | KKEY | KELLY & KELLY ENTERPRISE LLC | | | SCAC4 |
| 47 | KKFC | K K FARMS LLC | | | SCAC4 |
| 48 | KKFG | KUSMENKO KUSTOM FARMING | | | SCAC4 |
| 49 | KKFL | KROEKER FARMS LIMITED | | | SCAC4 |
| 50 | KKFU | KAWASAKI KISEN KAISHA LTD - K LINE | | J | BIC |
| 51 | KKFU | KAWASAKI KISEN KAISHA LTD | | | SCAC4 |
| 52 | KKFW | K & K FORWARDING (2008) LTD | | | SCAC4 |
| 53 | KKGC | KARAS & KARAS GLASS CO INC | | | SCAC4 |
| 54 | KKGE | KOOL KING EXPRESS INC | | | SCAC4 |
| 55 | KKGI | KK GROUP TRANSPORT INC | | | SCAC4 |
| 56 | KKHU | KANI KOMMERZ GMBH | | | SCAC3 |
| 57 | KKIP | KWIK KARGO INC TRANSPORT | | | SCAC4 |
| 58 | KKIT | KWIK KARGO INC TRUCKING | | | SCAC4 |
| 59 | KKJF | KURDZIONAK, JOHN F | | | SCAC4 |
| 60 | KKK | Atlasjet Uuslararasi Havacilik A/S | IATA: KK, Callsign: Atlasjet, IATA Prefix: 610, ICAO designator changed from OGE . IATA designator changed from 2U*. Name changed from Atlas International Airlines - Atlas International Havacilik A/S | TR | AVCODES |
| 61 | KKK | Atlasjet Airlines Inc | IATA: KK, Callsign: Atlasjet, IATA Prefix: 610, Name changed to AtlasGlobal Airlines. Name changed from Atlas International Airlines - Atlas International Havacilik A/S. ICAO designator changed from OGE . IATA designator changed from 2U* | TR | AVCODES |
| 62 | KKK | AtlasGlobal Airlines | IATA: KK, Callsign: Atlasjet, IATA Prefix: 610, Ceased operations on 12 February 2020. Name changed from Atlasjet Airlines Inc. Name changed from Atlas International Airlines - Atlas International Havacilik A/S. ICAO designator changed from OGE . IATA designator changed from 2U* | TR | AVCODES |
| 63 | KKK | Atlasjet | IATA: KK | | ICAO1 |
| 64 | KKKU | OZTURK KONTEYNER SAN VE TIC LTD STI | | TR | BIC |
| 65 | KKKU | TURKISH ARMY STAFF | | | SCAC4 |
| 66 | KKL | Kol-Kol Airlines Ltd. | Callsign: Kolkol Air, | WAN | AVCODES |
| 67 | KKLA | K & K LOGISTICS LLC | | | SCAC4 |
| 68 | KKLC | KOOL KARRIERS LLC | | | SCAC4 |
| 69 | KKLI | KING KONG LOGISTICS INC | | | SCAC4 |
| 70 | KKLL | KIRK LINE LIMITED | | | SCAC3 |
| 71 | KKLM | KEMP, K LOGISTICS LLC | | | SCAC4 |
| 72 | KKLO | KRIKELO SHIPPING S A | | | SCAC4 |
| 73 | KKLT | KOUNKEL TRUCKING LLC | | | SCAC4 |
| 74 | KKLU | KAWASAKI KISEN KAISHA LTD - K LINE | | J | BIC |
| 75 | KKLU | K LINE | | | PWRC |
| 76 | KKLU | K Line | | | RSRV |
| 77 | KKLU | K LINE (KAWASAKI KISEN KAISHA LTD) | | | SCAC3 |
| 78 | KKLU | KAWASAKI KISEN KAISHA LTD | | | SCAC4 |
| 79 | KKLZ | K LINE | | | PWRC |
| 80 | KKLZ | K Line | | | RSRV |
| 81 | KKLZ | K LINE | | | SCAC4 |
| 82 | KKMH | K & K MOBILE HOMES INC | | | SCAC3 |
| 83 | KKMJ | KITTRICK, MICHAEL J | | | SCAC3 |
| 84 | KKMN | KIRKMAN TRUCKING, INC | | | SCAC3 |
| 85 | KKMV | K & K MOVING | | | SCAC3 |
| 86 | KKMZ | KOKOMO RANGE | | | PWRC |
| 87 | KKNA | KAUKAUNA MEATS INC | | | SCAC4 |
| 88 | KKON | K KONCRETE INC (AN ILLINOIS CORP) | | | SCAC3 |
| 89 | KKPC | KLEIN KOSHER PICKEL COMPANY INC | | | SCAC4 |
| 90 | KKPS | KKP TRANSPORTATION SERVICES LTD | | | SCAC4 |
| 91 | KKPT | KIRKPATRICK SHIPPING INC. | | | SCAC3 |
| 92 | KKRE | K & K EXPRESS SERVICE INC | | | SCAC4 |
| 93 | KKRR | Knox & Kane R.R. Co. | added 10/1982; 1/1994-7/2005; eliminated 10/2006 | | NAKINA |
| 94 | KKRR | Knox & Kane R.R. Co. | added 10/82; 1/94-7/2000 | | NRHS |
| 95 | KKRR | KNOX & KANE RAILROAD COMPANY | | | PWRC |
| 96 | KKRR | Knox and Kane Railroad | | | RSRV |
| 97 | KKRR | KNOX & KANE RAILROAD COMPANY | | | SCAC3 |
| 98 | KKRS | KUSTOM KARRIERS LLC | | | SCAC4 |
| 99 | KKRV | K & K RECYCLING SERVICES | | | SCAC4 |
| 100 | KKRX | KASKASKIA REGIONAL PORT DISTRICT RAILROAD | | | PWRC |
