| 4901 | KSCP | KAPALUA SHIPPING CORPORATION | | | SCAC4 |
| 4902 | KSCQ | KINGS SPECIALIZED CARRIER INC | | | SCAC3 |
| 4903 | KSCR | KSI | | | SCAC4 |
| 4904 | KSCS | K & S CARRIERS LLC | | | SCAC4 |
| 4905 | KSCT | KORSTAR SHIPPING CO LTD | | | SCAC4 |
| 4906 | KSCU | KOREA SHIPPING CORPORATION | | | PWRC |
| 4907 | KSCU | Korea Shipping Corporation | | | RSRV |
| 4908 | KSCU | KOREA SHIPPING CORPORATION | | | SCAC3 |
| 4909 | KSCX | KapStone Charleston Kraft, LLC | added 10/2008 | | NAKINA |
| 4910 | KSCX | Kaiser Steel Corp. | 1/1952-7/1954; eliminated 1/1956; added 7/1966; 10/1966-1/1975; eliminated 7/1978 | | NAKINA |
| 4911 | KSCX | Kentucky Solvay Coke Co. (Ashland By-Product Coke Co.) | 7/1923 | | NAKINA |
| 4912 | KSCX | Kentucky Solvay Coke Co. | 8/1920 | | NAKINA |
| 4913 | KSCX | Kaiser Steel Corp. | 1/52; added 7/66; 10/66-1/75; eliminated 7/78 | | NRHS |
| 4914 | KSCX | *ASHLAND BY-PRODUCT COKE CO. [KENTUCKY SOLVAY COKE CO.] | | | PWRC |
| 4915 | KSCX | *KAISER STEEL CO. | | | PWRC |
| 4916 | KSCX | +KAPSTONE CHARLESTON KRAFT, LLC | | | PWRC |
| 4917 | KSCX | KAPSTONE CHARLESTON KRAFT LLC | | | SCAC4 |
| 4918 | KSCX | Kaiser Steel Corp. | | USA | TRAFFIC |
| 4919 | KSCY | KOFINAS SHIPPING COMPANY LIMITED | | | SCAC3 |
| 4920 | KSCY | K & S LOGISTICS INC | | | SCAC4 |
| 4921 | KSCZ | KOREA SHIPPING CORPORATION | | | PWRC |
| 4922 | KSCZ | Korea Shipping Corporation | | | RSRV |
| 4923 | KSCZ | KOREA SHIPPING CORPORATION | | | SCAC4 |
| 4924 | KSD | KAS Air Company | IATA: KW, Callsign: Aerokas, | KS | AVCODES |
| 4925 | KSDI | K/S DIFKO LXVII | | | SCAC4 |
| 4926 | KSDS | K & S DELIVERY SERVICE | | | SCAC3 |
| 4927 | KSE | Kiel-Segeberger Eisenbahn GmbH | | D | TRAFFIC |
| 4928 | KSEA | K-SEA TRANSPORTATION INC | | | SCAC4 |
| 4929 | KSEC | K I S S EXPRESS CO | | | SCAC3 |
| 4930 | KSEI | K & S ENTERPRISE INC | | | SCAC4 |
| 4931 | KSEL | K AND S EQUIPMENT LEASING INC | | | SCAC3 |
| 4932 | KSEN | KNUTSEN O A S SHIPPING A/S | | | SCAC3 |
| 4933 | KSEN | KNUTSEN O A S SHIPPING A/S | | | SCAC4 |
| 4934 | KSEQ | KASAN EQUIPMENT | | | SCAC3 |
| 4935 | KSET | K SEA TRANSPORTATION LLC | | | SCAC4 |
| 4936 | KSEU | PAPIERHAUS GMBH JESTEBURG | | D | BIC |
| 4937 | KSEV | KRIEGER SEASERVICES | | | SCAC4 |
| 4938 | KSEY | KASEY TRUCKING | | | SCAC3 |
| 4939 | KSF | Kent State University | Callsign: Kent, | USA | AVCODES |
| 4940 | KSFI | KEYSTONE FREIGHT INC | | | SCAC3 |
| 4941 | KSFL | KERNVILLE STAGE & FREIGHT LINES OF | | | SCAC3 |
| 4942 | KSFP | K & S FREIGHT TRANSPORT INC | | | SCAC4 |
| 4943 | KSFQ | KOSSAREFF, PHIL | | | SCAC3 |
| 4944 | KSFU | KING STAR FREIGHT PVT. LTD. | | IND | BIC |
| 4945 | KSFY | K & S FREIGHT | | | SCAC4 |
| 4946 | KSG | Kombiwaggon Servicegesellschaft | Mainz | D | privat-bahn.de |
| 4947 | KSG | Kopalnie i Zakłady Chemiczne Siarki “Siarkopol” S.A. | | PL | VKM |
| 4948 | KSGF | KASSENBORG, GORDON FARMS INC | | | SCAC3 |
| 4949 | KSGL | KGL TRANSPORT LTD | | | SCAC4 |
| 4950 | KSGQ | KENNEY, S G TRUCKING CORPORATION | | | SCAC3 |
| 4951 | KSGT | KENSINGTON TRUCKING INC | | | SCAC3 |
| 4952 | KSGU | KWIKSPACE GUAM INC | | | SCAC4 |
| 4953 | KSH | Pan Mediterranean Aviation (PMA) | Callsign: Sunlight, | SYR | AVCODES |
| 4954 | KSHC | KRASNAGORSK SHIPPING CO LTD | | | SCAC3 |
| 4955 | KSHD | KISHIDA, NOBUO | | | SCAC3 |
| 4956 | KSHE | KSH EXPRESS INC | | | SCAC4 |
| 4957 | KSHI | KENTUCKIANA SHIPPING INTERNATIONAL | | | SCAC3 |
| 4958 | KSHI | KURSCHAT TRUCKING | | | SCAC4 |
| 4959 | KSHL | KINGSLAND SHIPPING LTD MONROVIA LIB | | | SCAC3 |
| 4960 | KSHN | KAMRUDIM | | | SCAC4 |
| 4961 | KSHP | KENWA SHIPPING COMPANY LIMITED | | | SCAC3 |
| 4962 | KSHP | KENWA SHIPPING COMPANY LIMITED | | | SCAC4 |
| 4963 | KSHQ | KISHLER, CHARLES L | | | SCAC3 |
| 4964 | KSHS | KSH SHIPPING PTD LTD. | | | SCAC3 |
| 4965 | KSHS | KSH SHIPPING PTD LTD. | | | SCAC4 |
| 4966 | KSHW | KINGS HIGHWAY | | | SCAC4 |
| 4967 | KSHX | State Highway Commission of Kansas | 7/1932-4/1938 | | NAKINA |
| 4968 | KSHX | State Highway Commission of Kansas | Apr-38 | | NRHS |
| 4969 | KSHX | STATE HIGHWAY COMMISSION OF KANSAS | | | PWRC |
| 4970 | KSHY | KLASSEN SPECIALTY HYDRAULICS INC | | | SCAC4 |
| 4971 | KSI | Air Kissari, Transporte Aereo | Callsign: Kissari, | ANG | AVCODES |
| 4972 | KSI | Air Kissari | | | ICAO1 |
| 4973 | KSIA | KINGDOM STEAMSHIP INC | | | SCAC4 |
| 4974 | KSIC | KOSTA INTERNATIONAL CORP. | | | SCAC3 |
| 4975 | KSIC | KENMORE SHIPPING INC | | | SCAC4 |
| 4976 | KSII | KESSLER TRANSPORTATION INC | | | SCAC3 |
| 4977 | KSIN | KARESA INC | | | SCAC4 |
| 4978 | KSIU | LLC KISLOROD PREMIUM | | RUS | BIC |
| 4979 | KSJ | K2 Smart Jets | Callsign: Kay-jets, | GR | AVCODES |
| 4980 | KSJO | KELLER, STEPHEN J | | | SCAC4 |
| 4981 | KSK | Kas Air Company | IATA: KW, | KZ | AVCODES |
| 4982 | KSK | Klub Sympatyków Kolei | | PL | VKM |
| 4983 | KSKC | KUESTER TRUCKING LTD | | | SCAC4 |
| 4984 | KSKD | KIOSK DIMENSIONS INC | | | SCAC4 |
| 4985 | KSKG | K'S TRUCKING | | | SCAC4 |
| 4986 | KSKI | K & S TANK LINES INC | | | SCAC4 |
| 4987 | KSKL | KERNER & SINKLER TRUCKING | | | SCAC3 |
| 4988 | KSKL | KERNER TRANSPORTATION | | | SCAC4 |
| 4989 | KSKN | K & S TRUCKING | | | SCAC4 |
| 4990 | KSKO | KILLINS TRUCKING INC | | | SCAC4 |
| 4991 | KSKQ | KURILSK SHIPPING COMPANY, LTD. | | | SCAC3 |
| 4992 | KSKQ | KSK LINE INC | | | SCAC4 |
| 4993 | KSKR | KUSTOM KOURIER INC | | | SCAC3 |
| 4994 | KSKR | KUSTOM KOURIER INC | | | SCAC4 |
| 4995 | KSKR | Kusakaru Electric Railway | | J | TRAFFIC |
| 4996 | KSKT | KOST, KELLY TRUCKING | | | SCAC3 |
| 4997 | KSKV | KAPITAN SOKOLOV SHIPPING CO. LTD. | | | SCAC3 |
| 4998 | KSL | Koleie Slaskie | | PL | TRAFFIC |
| 4999 | KSL | Koleje Śląskie Sp. z o.o. | | PL | VKM |
| 5000 | KSLC | KAC SERVICES LLC | | | SCAC4 |
