| 4701 | KRR | Kiamichi R.R. Co., L.L.C. | added 10/1996; 7/2000-7/2005 | | NAKINA |
| 4702 | KRR | Kiamichi R.R. Co., Inc. | added 1/1988; 1/1994; eliminated 10/1996 | | NAKINA |
| 4703 | KRR | Kiamichi R.R. Co., Inc. | added 1/88; 1/94; eliminated 10/96 | | NRHS |
| 4704 | KRR | Kiamichi R.R. Co., L.L.C. | added 10/96; 7/2000 | | NRHS |
| 4705 | KRR | KIAMICHI RAILROAD CO., LLC | | | PWRC |
| 4706 | KRR | Kiamichi Railroad | | | RSRV |
| 4707 | KRR | KIAMICHI RAILROAD COMPANY LLC | | | SCAC4 |
| 4708 | KRR | Kiamichi R.R. Co., L.L.C. | | USA | TRAFFIC |
| 4709 | KRRB | KERRIGAN BROS INC | | | SCAC3 |
| 4710 | KRRC | KERR COACH | | | SCAC3 |
| 4711 | KRRC | KERR, COLIN HOLDINGS LTD | | | SCAC4 |
| 4712 | KRRG | KREGER TRANSPORT INC | | | SCAC4 |
| 4713 | KRRI | KARRIE TRANSPORTATION INC | | | SCAC3 |
| 4714 | KRRL | KRAUSE, R L TRUCKING INC | | | SCAC3 |
| 4715 | KRRL | K & R TRANSPORT II LLC | | | SCAC4 |
| 4716 | KRRN | KEMCO RESOURCES INC | | | SCAC4 |
| 4717 | KRRP | KRISP TRUCKING INC | | | SCAC4 |
| 4718 | KRRS | K & R REPAIR SERVICE INC | | | SCAC4 |
| 4719 | KRRT | KRUEGER, R TRUCKING | | | SCAC3 |
| 4720 | KRRW | KERR, WILMER L | | | SCAC3 |
| 4721 | KRRY | KARRY ALL ENTERPRISES LLC | | | SCAC4 |
| 4722 | KRS | Kyrgyz International Airlines | IATA: N5, Callsign: Kyrmal, IATA Prefix: 987, ICAO designator changed to KYL | KS | AVCODES |
| 4723 | KRS | Korsar | Callsign: Korsar Avia, | RUS | AVCODES |
| 4724 | KRS | Rosen Aviation Inc | | J | AVCODES |
| 4725 | KRS | Air Company Course-S | Callsign: Atlas, | RUS | AVCODES |
| 4726 | KRSA | KRITSAS SHIPPING S A | | | SCAC3 |
| 4727 | KRSA | KRISTIS ANTIQUES INC | | | SCAC4 |
| 4728 | KRSC | KRAMMER M STORAGE CORP | | | SCAC3 |
| 4729 | KRSE | KIRSCH ENTERPRISES | | | SCAC3 |
| 4730 | KRSF | KRASDALE FOOD INC | | | SCAC3 |
| 4731 | KRSG | KROSSNES SHIPPING INC | | | SCAC3 |
| 4732 | KRSK | KRISKA TRANSPORTATION | | | SCAC4 |
| 4733 | KRSL | KRASILOVSKY, MILTON, INC | | | SCAC3 |
| 4734 | KRSL | KASCHPER RACING SHELLS LTD | | | SCAC4 |
| 4735 | KRSM | KRIST OIL COMPANY | | | SCAC4 |
| 4736 | KRSN | K R S TRUCKING CORPORATION | | | SCAC3 |
| 4737 | KRSN | KRUSE NATIONWIDE INC | | | SCAC4 |
| 4738 | KRSP | Kronospan Sebes | | RO | TRAFFIC |
| 4739 | KRSQ | KERST TRUCKING | | | SCAC3 |
| 4740 | KRSR | KROSS ROADS TRANSPORTATION OF IDAHO | | | SCAC3 |
| 4741 | KRSR | KRS TRANSPORT LTD | | | SCAC4 |
| 4742 | KRSS | KRAUSS LEASING INC | | | SCAC3 |
| 4743 | KRST | KARS TRANSPORT INC | | | SCAC3 |
| 4744 | KRSU | {LLP "KRASPROM"};ZIPCODE=656011 | | RUS | BIC |
| 4745 | KRSV | KREST SERVICE | | | SCAC3 |
| 4746 | KRSX | Kurguz Enterprises Inc. d/b/a Kurguz Railway Services | 7/2005 (not listed) | | NAKINA |
| 4747 | KRSX | *KAYEN RAIL CAR SERVICE INC. | | | PWRC |
| 4748 | KRSX | +KURGUZ ENTERPRISES, INC d/b/a KURGUZ RAILWAY SERVICES | | | PWRC |
| 4749 | KRSX | Kurguz Railway Services | | | RSRV |
| 4750 | KRSX | KURGUZ RAILWAY SERVICES | | | SCAC4 |
| 4751 | KRT | Kokshetau Airline | Callsign: Kokta, Name changed to Aircompany Kokehetau | KZ | AVCODES |
| 4752 | KRT | Cretan Airlines | IATA: C5, Callsign: Cretan, Ceased operations | GR | AVCODES |
| 4753 | KRT | Aircompany Kokshetau JSC | IATA: 0K, Callsign: Kokta, Name changed from Kokshetau Airline | KZ | AVCODES |
| 4754 | KRT | Kirknewton (RAF) | Callsign: Kirknewton, | GB | AVCODES |
| 4755 | KRT | Air Kokshetau | | | ICAO1 |
| 4756 | KRT | Kashima Rinkai Railway | | J | TRAFFIC |
| 4757 | KRTA | K&R TRANSPORTATION, INC | | | SCAC3 |
| 4758 | KRTA | KARRAKER TRANSPORT | | | SCAC4 |
| 4759 | KRTB | KRAFTOURS TRAVEL INC | | | SCAC3 |
| 4760 | KRTC | KRT LOGISTICS INC | | | SCAC4 |
| 4761 | KRTD | K&R TRANSPORTATION, INC | | | SCAC3 |
| 4762 | KRTD | K & R TRANSPORTATION LLC | | | SCAC4 |
| 4763 | KRTE | KRT ENTERPRISES INC | | | SCAC3 |
| 4764 | KRTE | K & R TRUCKING | | | SCAC4 |
| 4765 | KRTF | KRAMER TRANSFER & STORAGE INC | | | SCAC3 |
| 4766 | KRTG | KRUEPKE TRUCKING INC | | | SCAC3 |
| 4767 | KRTH | KORTH TRANSFER INC | | | SCAC3 |
| 4768 | KRTH | KIMBALL, ROGER TRANSPORTATION INC | | | SCAC4 |
| 4769 | KRTI | K & R TRUCKING COMPANY | | | SCAC3 |
| 4770 | KRTI | KOEHN, RON TRUCKING INC | | | SCAC4 |
| 4771 | KRTJ | KRISTIJANTO, ANTON INC | | | SCAC4 |
| 4772 | KRTK | KERNS TRUCKING INC | | | SCAC3 |
| 4773 | KRTK | KERNS TRUCKING INC | | | SCAC4 |
| 4774 | KRTL | K & R TRANSPORTATION AND LOGISTICS | | | SCAC4 |
| 4775 | KRTM | KERSTEN TRUCKING INC | | | SCAC3 |
| 4776 | KRTM | KURAMOTO, TOM | | | SCAC4 |
| 4777 | KRTN | KRISTEN NAVIGATION | | | SCAC3 |
| 4778 | KRTN | KRISTEN NAVIGATION INC | | | SCAC4 |
| 4779 | KRTQ | KRUGER TRANSFER INC | | | SCAC3 |
| 4780 | KRTR | KRESSIN TRUCKING NC | | | SCAC3 |
| 4781 | KRTS | KREIDER TRANSPORTATION SERVICE INC | | | SCAC3 |
| 4782 | KRTT | KR TRANSPORT | | | SCAC3 |
| 4783 | KRTT | KRAUSS TRUCKING INC | | | SCAC4 |
| 4784 | KRTU | KRAMPITZ TRANKSYSTEM GMBH | | D | BIC |
| 4785 | KRTU | KRAMPITZ TANKSYSTEM GMBH | | | SCAC4 |
| 4786 | KRTV | KRANS TRUCKING | | | SCAC3 |
| 4787 | KRTW | K R TRUCKING | | | SCAC4 |
| 4788 | KRTX | Kendall Refining Co. | 8/1920; 7/1937-4/1938; 1/1946 (not listed) | | NAKINA |
| 4789 | KRTX | Kendall Refining Co. | Apr-38 | | NRHS |
| 4790 | KRTX | *KENDALL REFINING CO. | | | PWRC |
| 4791 | KRTX | *KANAWHA RIVER TERMINAL | | | PWRC |
| 4792 | KRTY | KIRTLEY TRUCKING COMPANY, INC | | | SCAC3 |
| 4793 | KRU | Karun Airlines | IATA: NV, Callsign: Karun, IATA Prefix: 346, Name changed from Iranian Naft Airlines in September 2017. | IR | AVCODES |
| 4794 | KRUB | KRUMHOLZ, BERNARD | | | SCAC3 |
| 4795 | KRUD | KRUEGER, DONALD R | | | SCAC3 |
| 4796 | KRUE | KRUEGER, EARL, TRUCKING | | | SCAC3 |
| 4797 | KRUH | KRUSE, HARLEY P | | | SCAC3 |
| 4798 | KRUI | KRUEPKE TRUCKING INC | | | SCAC4 |
| 4799 | KRUJ | KRUJEX TRANSPORT CORP | | | SCAC4 |
| 4800 | KRUP | KRUPINSKI INC | | | SCAC4 |
