| 1 | KC | Kiwi Travel International Airlines | ICAO: KIC, Callsign: Kaytac, Ceased operations | NZ | AVCODES |
| 2 | KC | Carpathian Air Transport Ltd. | ICAO: CPP, Callsign: Carpatian, Designator changed to KC | H | AVCODES |
| 3 | KC | Carpathian Air Transport Ltd. | ICAO: CPP, Callsign: Carpatian, Designator KC recalled by IATA. Designator changed from KC* | H | AVCODES |
| 4 | KC | Cargoair New Zealand Ltd. | Designator KC recalled by IATA | NZ | AVCODES |
| 5 | KC | Cameroons Air Transport LTd. | | CAM | AVCODES |
| 6 | KC | Trans Atlantic Airlines | | USA | AVCODES |
| 7 | KC | Air Astana | ICAO: KZR, Callsign: Astanaline, IATA Prefix: 465, IATA designator changed from 4L w.e.f. 29 October 2006. ICAO designator changed from AST. IATA Designator changed from LQ* | KZ | AVCODES |
| 8 | KC | The Kanawha Central Ry. Co. | 1/1975 | | NAKINA |
| 9 | KC | The Kanawha Central Ry. Co. | Jan-75 | | NRHS |
| 10 | KC | KANAWHA CENTRAL RAILROAD CO. | | | PWRC |
| 11 | KC | KOLEJE CZESKIE Sp. z o.o. | | PL | VKM |
| 12 | KCA | Trans-Kiev | Callsign: Trans-Kiev, Name changed to Aviatrans K Ltd, Air Company. | UA | AVCODES |
| 13 | KCA | Chosonmihang CAA of DPR of Korea | IATA: JS, Callsign: Juliett Sierra, ICAO designator changed frm CSM | PRK | AVCODES |
| 14 | KCA | Chosonmihang CAA of DPR of Korea | IATA: JS, Callsign: Air Korea, Name changed to Air Koryo. ICAO designator changed frm CSM | PRK | AVCODES |
| 15 | KCA | Aviatrans K Ltd, Air Company | IATA: KI, Callsign: Trans Kiev, Name changed from Trans-Kiev. | UA | AVCODES |
| 16 | KCA | Trans-Kiev | | | ICAO1 |
| 17 | KCAC | K-C AND COMPANY TRUCKING | | | SCAC3 |
| 18 | KCAG | KEANS CARTAGE INC | | | SCAC3 |
| 19 | KCAIRPORT | Kansas City International Airport | | USA | TRAFFIC |
| 20 | KCAP | KOENIGS CUSTOM APPLICATION | | | SCAC4 |
| 21 | KCAR | KAIM CARRIERS | | | SCAC4 |
| 22 | KCAS | K C & SON TOOL & EQUIPMENT RENTAL | | | SCAC3 |
| 23 | KCAS | KANZA COOPERATIVE ASSOCIATION | | | SCAC4 |
| 24 | KCATA | Kansas City Area Transportation Authority | | USA | TRAFFIC |
| 25 | KCAX | KCAC, Inc. | added 10/1985; eliminated 1/1987 | | NAKINA |
| 26 | KCAX | KCAC, Inc. | eliminated 1/87 | | NRHS |
| 27 | KCAX | KCAC INC. | | | PWRC |
| 28 | KCBU | IMOTO LINES, LTD. | | J | BIC |
| 29 | KCBU | SUMISHO GLOBAL LOGISTICS CO LTD | | | SCAC4 |
| 30 | KCBX | KCBX TERMINALS CO. | | | PWRC |
| 31 | KCC | Kansas City Connecting R.R. Co. | 1/1975-1/1980 | | NAKINA |
| 32 | KCC | Kansas City Connecting R.R. Co. | 1/75-1/80 | | NRHS |
| 33 | KCC | KANSAS CITY CONNECTING RAILROAD CO. | | | PWRC |
| 34 | KCCI | K C CARTAGE INC | | | SCAC3 |
| 35 | KCCI | K C TRANSPORTATION INC | | | SCAC4 |
| 36 | KCCL | KCC TRANSPORT SYSTEMS INC | | | SCAC3 |
| 37 | KCCL | KCC TRANSPORT SYSTEMS INC | | | SCAC4 |
| 38 | KCCN | KUNSHEK CHAT & COAL INC | | | SCAC3 |
| 39 | KCCP | KINDER CARTAGE CORP | | | SCAC3 |
| 40 | KCCP | K C COMPANY | | | SCAC4 |
| 41 | KCCQ | KANSAS CITY COMMERCIAL CARTAGE CO I | | | SCAC3 |
| 42 | KCCQ | K & C CONTRACTORS INC | | | SCAC4 |
| 43 | KCCS | KANSAS CITY COLD STORAGE & ICE | | | SCAC4 |
| 44 | KCCX | Kennecott Utah Copper Corp. | added 4/1991; 1/1994-7/2005 | | NAKINA |
| 45 | KCCX | Kennecott Corp. | added 4/1981; eliminated 4/1991 | | NAKINA |
| 46 | KCCX | Kennecott Copper Corp. | added 4/1970; 4/1970-1/1980; eliminated 4/1981 | | NAKINA |
| 47 | KCCX | Kimberly-Clark Co. | 7/1937-4/1961 | | NAKINA |
| 48 | KCCX | Kimberly-Clark Corp. | 7/1930-7/1935 | | NAKINA |
| 49 | KCCX | Kimberly-Clark Co. | 4/38-4/61 | | NRHS |
| 50 | KCCX | Kennecott Copper Corp. | added 4/70; 4/70-1/80; eliminated 4/81 | | NRHS |
| 51 | KCCX | Kennecott Corp. | added 4/81; eliminated 4/91 | | NRHS |
| 52 | KCCX | Kennecott Utah Copper Corp. | added 4/91; 1/94-7/2000 | | NRHS |
| 53 | KCCX | *KIMBERLY-CLARK CO. | | | PWRC |
| 54 | KCCX | +KENNECOTT UTAH COPPER CORPORATION | | | PWRC |
| 55 | KCCX | Kennecott Utah Copper Corporation | | | RSRV |
| 56 | KCCX | KENNECOTT UTAH COPPER CORPORATION | | | SCAC4 |
| 57 | KCCX | Kennecott Copper Corp. | | USA | TRAFFIC |
| 58 | KCCY | KDC CONSTRUCTION COMPANY | | | SCAC4 |
| 59 | KCCZ | KAISER CEMENT COMPANY | | | PWRC |
| 60 | KCDC | KRAFT FOODSERVICE INC | | | SCAC3 |
| 61 | KCDI | KUTCHIN OF CANADA INC | | | SCAC4 |
| 62 | KCDL | K C DEDICATED LLC | | | SCAC4 |
| 63 | KCDS | KATIE COURIER & DELIVERY SERVICE IN | | | SCAC4 |
| 64 | KCDT | KCD TRANSPORT | | | SCAC3 |
| 65 | KCDU | KALYPSO COMPAGNIA DI NAVIGAZIONE SPA | | I | BIC |
| 66 | KCDU | KALI-CHEMIE A.G. | | | SCAC3 |
| 67 | KCDX | Eastman Kodak Co. | added 1/1976; 1/1980-7/2000; eliminated 7/2005; 7/2005 (not listed) | | NAKINA |
| 68 | KCDX | Eastman Kodak Co. | 1/80-7/2000 | | NRHS |
| 69 | KCDX | EASTMAN KODAK CO | | | PWRC |
| 70 | KCDX | Eastman Kodak | | | RSRV |
| 71 | KCE | K C Piper Sales, Inc. | Callsign: KayCee, | USA | AVCODES |
| 72 | KCE | Irving Oil Transport Ltd. | Callsign: Kacey, | CDN | AVCODES |
| 73 | KCE | Irving Oil Transport | | | ICAO1 |
| 74 | KCEI | KIFF, C E INC | | | SCAC4 |
| 75 | KCEM | KCE INC | | | SCAC4 |
| 76 | KCEN | KRAMER-CAS | | | SCAC4 |
| 77 | KCEP | KC EXPRESS INC | | | SCAC3 |
| 78 | KCES | KC EXPRESS (KC FREIGHT SYSTEMS INC | | | SCAC3 |
| 79 | KCEX | Kazco Enterprises, Inc. | 7/2005 (not listed) | | NAKINA |
| 80 | KCEX | KAZCO ENTERPRISES, INC. | | | PWRC |
| 81 | KCEX | KAZCO ENTERPRISES INC | | | SCAC4 |
| 82 | KCFI | K C FORWARDING INC | | | SCAC3 |
| 83 | KCFQ | KEPPLER, CHARLES F | | | SCAC3 |
| 84 | KCFT | KCF TRANSPORTATION | | | SCAC4 |
| 85 | KCGF | K C GIFTS | | | SCAC4 |
| 86 | KCGM | K.C.G.M. TRANSPORT | | | SCAC3 |
| 87 | KCGM | K C G M TRANSPORT | | | SCAC4 |
| 88 | KCGO | KEEN COMPRESSED GAS CO | | | SCAC4 |
| 89 | KCGT | KCG TRANSPORT LLC | | | SCAC4 |
| 90 | KCGX | Cemex, Inc. | added 7/2005; 7/2005 | | NAKINA |
| 91 | KCGX | Southdown, Inc. | added 1/1997; eliminated 7/1997; 7/2000 (not listed) | | NAKINA |
| 92 | KCGX | Mitsubishi Cement Corp. | added 1/1990; 1/1994; eliminated 1/1997 | | NAKINA |
| 93 | KCGX | Kaiser Cement Corp. | added 1/1980; 1/1980; eliminated 1/1990 | | NAKINA |
| 94 | KCGX | Kaiser Cement & Gypsum Corp. | added 10/1965; 10/1966-1/1975; eliminated 1/1980 | | NAKINA |
| 95 | KCGX | Kaiser Cement & Gypsum Corp. | added 10/65; 10/66-1/75; eliminated 1/80 | | NRHS |
| 96 | KCGX | Kaiser Cement Corp. | added 1/80; 1/80; eliminated 1/90 | | NRHS |
| 97 | KCGX | Mitsubishi Cement Corp. | added 1/90; 1/94; eliminated 1/97 | | NRHS |
| 98 | KCGX | Southdown, Inc. | added 1/97; eliminated 7/97; 7/2000 | | NRHS |
| 99 | KCGX | *MITSUBISHI CEMENT CORPORATION [KAISER CEMENT CORP.] | | | PWRC |
| 100 | KCGX | *SOUTHDOWN INCORPORATED | | | PWRC |
