| 4801 | KRUPP | Krupp Stahl AG | | D | TRAFFIC |
| 4802 | KRUQ | KREUGER TRUCKING CO INC | | | SCAC3 |
| 4803 | KRUR | KRUG, PHIL TRUCKING | | | SCAC3 |
| 4804 | KRUS | KRUSE TRUCKING CO | | | SCAC3 |
| 4805 | KRV | Khoriv-Avia, State Enterprise | Callsign: Khoriv-Avia, | UA | AVCODES |
| 4806 | KRV | Khoriv-Avia | | | ICAO1 |
| 4807 | KRVC | KRV CONSTRUCTION INC | | | SCAC4 |
| 4808 | KRVM | KETTLE RIVER MECHANICAL INC | | | SCAC3 |
| 4809 | KRVN | KERN, IVAN A | | | SCAC3 |
| 4810 | KRVS | KARVIS TRUCKING INC | | | SCAC3 |
| 4811 | KRVT | KERVIN, T J TRUCKING COMPANY | | | SCAC3 |
| 4812 | KRWC | K A R TRANSPORT | | | SCAC3 |
| 4813 | KRWF | KETTLE RIVER WOODCRAFT | | | SCAC4 |
| 4814 | KRWI | KRW INC | | | SCAC3 |
| 4815 | KRWI | KRWX INC | | | SCAC4 |
| 4816 | KRWJ | KERR TRANSPORTATION INC | | | SCAC3 |
| 4817 | KRWN | KERWIN TANK LINES INC | | | SCAC3 |
| 4818 | KRWR | KRUG, W R | | | SCAC3 |
| 4819 | KRWS | KERR, W D & SONS INC | | | SCAC3 |
| 4820 | KRWT | KROWN TRANSPORTATION INC | | | SCAC3 |
| 4821 | KRWX | Kalamazoo Rendering Works, Inc. | added 4/1955; 10/1957; eliminated 10/1959 | | NAKINA |
| 4822 | KRWX | Kalamazoo Rendering Works | eliminated 4/1955 | | NAKINA |
| 4823 | KRWX | Kalamazoo Rendering Works, Inc. | 1/1945-7/1954 | | NAKINA |
| 4824 | KRWX | kalamazoo Rendering Works | 1/52; eliminated 4/55 | | NRHS |
| 4825 | KRWX | kalamazoo Rendering Works, Inc. | added 4/55; 10/57; eliminated 10/59 | | NRHS |
| 4826 | KRWX | KALAMAZOO RENDERING WORKS, INC. | | | PWRC |
| 4827 | KRX | The Kettle River Co. | 8/1920 | | NAKINA |
| 4828 | KRX | KETTLE RIVER CO. | | | PWRC |
| 4829 | KRXI | K R X INC | | | SCAC3 |
| 4830 | KRXP | KROBLIN REFRIGERATED EXPRESS INC | | | SCAC3 |
| 4831 | KRYC | KRYSTAL CORP, | | | SCAC3 |
| 4832 | KRYC | KARYCY TRANSPORTACIONES SA DE CV | | | SCAC4 |
| 4833 | KRYL | KRYSTAL TRUCKING | | | SCAC3 |
| 4834 | KRYP | KRYPTON EXPRESS | | | SCAC4 |
| 4835 | KRYQ | K-R-Y | | | SCAC3 |
| 4836 | KRYT | KRYSTEL TRANSPORT | | | SCAC3 |
| 4837 | KRYT | KRYSTEL TRANSPORT | | | SCAC4 |
| 4838 | KRZA | KURZ-ALLEN INC | | | SCAC3 |
| 4839 | KRZD | KARDENIZ DENIZCILIK ISLETMELERI AS | | | SCAC4 |
| 4840 | KRZD | Crimea Railway | | | TRAFFIC |
| 4841 | KRZE | KRAZE TRUCKING | | | SCAC4 |
| 4842 | KRZF | KRUZOFF TRAVEL | | | SCAC3 |
| 4843 | KRZL | KREUTZER & CO (2008) LTD | | | SCAC4 |
| 4844 | KRZQ | KARZEN TRUCKING CO | | | SCAC3 |
| 4845 | KRZR | KROTZER HAULING SERVICE | | | SCAC3 |
| 4846 | KRZT | KRUIZE TRUCKING | | | SCAC3 |
| 4847 | KRZT | KRAZE LOGISTICS LLC | | | SCAC4 |
| 4848 | KRZW | KURZWEG, HAROLD J | | | SCAC3 |
| 4849 | KS | Peninsula Airways, Inc. t/a PenAir | ICAO: NLA, Callsign: Peninsula, IATA Prefix: 339, IATA designator KS recalled by IATA. | USA | AVCODES |
| 4850 | KS | Casair Aviation Services Ltd. | | GB | AVCODES |
| 4851 | KS | Saturn Airways, Inc. | Callsign: Saturn, | USA | AVCODES |
| 4852 | KS | Casair Aviation Ltd. | ICAO: CSL, Callsign: Casair, | GB | AVCODES |
| 4853 | KS | Air Connect Aviation Group | ICAO: KON, Callsign: Air Connect, Plans to launch flights with an ATR72-600 turboprop in May 2022. | RO | AVCODES |
| 4854 | KS | Kolding Sydbaner | 1911 - 1948 | DK | jernbanen.dk |
| 4855 | KS | KANSAS CITY STAR | | | PWRC |
| 4856 | KS | Kobenhavns Sporveje | City: Koppenhagen | DK | TRAFFIC |
| 4857 | KS | KOTOUČ ŠTRAMBERK, spol. s r.o. | | CZ | VKM |
| 4858 | KSA | Sud Aerocargo | Callsign: Sudcargo, | MD | AVCODES |
| 4859 | KSA | KS Avia | Callsign: Sky Camel, | LV | AVCODES |
| 4860 | KSA | K S Avia | | | ICAO1 |
| 4861 | KSAF | KOSTER, ALFRONS AND CO. | | | SCAC3 |
| 4862 | KSAG | KOWALSKI SAUSAGE CO | | | SCAC4 |
| 4863 | KSAK | KRITSAK TRUCKING | | | SCAC4 |
| 4864 | KSAN | K S ATHWAL TRANSPORT INC | | | SCAC4 |
| 4865 | KSAS | KONKAR SHIPPING AGENCIES S A | | | SCAC3 |
| 4866 | KSAS | KONKAR SHIPPING AGENCIES S A | | | SCAC4 |
| 4867 | KSAT | KOCTUG SHIPPING & TRADING INC | | | SCAC3 |
| 4868 | KSAT | K/S ALTAIR SHIPPING | | | SCAC4 |
| 4869 | KSAT | Kushiro Satellite Co. Ltd. | | J | TRAFFIC |
| 4870 | KSAU | KSAN SIA | | LV | BIC |
| 4871 | KSAU | KSAN SIA | | | SCAC4 |
| 4872 | KSAV | KEY STATE AG SERVICE | | | SCAC4 |
| 4873 | KSAY | KING STAR TRUCKING LTD | | | SCAC4 |
| 4874 | KSB | København - Slangerup Banen (Slangerupbanen) | 1906 - 1948 | DK | jernbanen.dk |
| 4875 | KSB | København - Slangerup Banen (Slangerupbanen) | 1906 - 1948 | DK | TRAFFIC |
| 4876 | KSBI | KOCH SCHOOL BUS SERVICE INC | | | SCAC4 |
| 4877 | KSBK | KEYSTONE BULK TRANSPORT LTD | | | SCAC3 |
| 4878 | KSBK | K & J LOGISTICS INC | | | SCAC4 |
| 4879 | KSBL | KICKERT SCHOOL BUS LINE INC | | | SCAC3 |
| 4880 | KSBS | KEYSTONE BUS SERVICE INC | | | SCAC3 |
| 4881 | KSBU | GUANGDONG BESTCON INTELLIGENT EQUIPMENT CO., LTD. | | PRC | BIC |
| 4882 | KSBW | K & S BONDED WAREHOUSE INC | | | SCAC3 |
| 4883 | KSC | Krajowa Spółka Cukrowa S.A. | | PL | VKM |
| 4884 | KSCA | K & S TRANSPORT INC | | | SCAC4 |
| 4885 | KSCB | KB & SONS CARRIER LTD | | | SCAC4 |
| 4886 | KSCC | KANSAS CITY COLD STORAGE DISTRIBUTION INC. | | | PWRC |
| 4887 | KSCC | KANSAS CITY COLD STORAGE DISTRIBUTI | | | SCAC3 |
| 4888 | KSCC | KOL GLOBAL LOGISTICS SERVICES | | | SCAC4 |
| 4889 | KSCD | KYOWA SHIPPING CO LTD | | | SCAC3 |
| 4890 | KSCD | K-SOURCE CANADA LTD | | | SCAC4 |
| 4891 | KSCE | KANSAS CITY EXPRESS | | | SCAC3 |
| 4892 | KSCF | KLEGSTAD, SCOTT | | | SCAC4 |
| 4893 | KSCH | KLEINSCHMIT TRUCKING INC | | | SCAC4 |
| 4894 | KSCH | Kiel-Schönberger Eisenbahn GmbH | | D | TRAFFIC |
| 4895 | KSCI | KANAWHA STONE COMPANY INC | | | SCAC4 |
| 4896 | KSCL | KOMI SHIPPING COMPANY LTD LIB | | | SCAC3 |
| 4897 | KSCL | KESCO CONTAINER LINE INC | | | SCAC4 |
| 4898 | KSCM | KENNEDY-SIM | | | SCAC4 |
| 4899 | KSCN | KOSCARGO CONSOLID CORP. | | | SCAC3 |
| 4900 | KSCO | K/S COMBI LIFT | | | SCAC4 |
