| 601 | KBLT | K & B TRANSPORT INC | | | SCAC4 |
| 602 | KBLV | KURTENBACH LIVESTOCK LLC | | | SCAC4 |
| 603 | KBLX | CanAM Minerals, Inc. | added 10/2006; eliminated 4/2008 | | NAKINA |
| 604 | KBLX | CANAM MINERALS, INC. | | | PWRC |
| 605 | KBLX | CANAM MINERALS INC | | | SCAC4 |
| 606 | KBME | KBM EQUIPMENT REPAIR INC | | | SCAC4 |
| 607 | KBMF | KBM FORESTRY CONSULTANTS INC | | | SCAC4 |
| 608 | KBMG | KBM TRUCKING | | | SCAC4 |
| 609 | KBMH | KELSO, BOB MOBILE HOME TRANSPORT AN | | | SCAC3 |
| 610 | KBML | KNIGHTS BUILDING MATERIALS INC | | | SCAC3 |
| 611 | KBMS | KONICA BUSINESS MACHINES U S A INC | | | SCAC3 |
| 612 | KBMT | K B M TRANSPORT INC | | | SCAC3 |
| 613 | KBMW | KAPTANOGLU BROTHERS MARITIME LTD | | | SCAC4 |
| 614 | KBN | Sriracha Aviation Co. Ltd. | Callsign: Kabin, | T | AVCODES |
| 615 | KBNA | KARR, BUD & ASSOCIATES INC | | | SCAC3 |
| 616 | KBO | Aero Tours (Newcastle) Ltd. | Callsign: Tyne, | GB | AVCODES |
| 617 | KBOS | K & B OIL SUPPLY INC | | | SCAC4 |
| 618 | KBOT | KUHN BROTHERS TRUCKING COMPANY | | | SCAC3 |
| 619 | KBPI | K B PIZZA INC | | | SCAC4 |
| 620 | KBPT | KRAMER BROTHERS PETROLEUM TRANSPORT | | | SCAC3 |
| 621 | KBR | KoralBlue Airlines | IATA: K7, Callsign: Koral Blue, Ceased operations 2011 | ET | AVCODES |
| 622 | KBRC | KOERNER, BRUCE R CRANES AND | | | SCAC4 |
| 623 | KBRE | KENBRENT REFRIGERATED EXPRESS LTD | | | SCAC3 |
| 624 | KBRG | KOCHBERG GRAPHICS INC | | | SCAC4 |
| 625 | KBRI | K B RECYCLING INC | | | SCAC4 |
| 626 | KBRO | KING BROS FREIGHT SERVICE | | | SCAC3 |
| 627 | KBRO | KING BROS INDUSTIRES | | | SCAC4 |
| 628 | KBRT | KLOSINSKI BROTHERS INC | | | SCAC3 |
| 629 | KBS | Business Aero, LLC | | RUS | AVCODES |
| 630 | KBS | KOLEJ BAŁTYCKA - SERWIS Sp. z o.o. | | PL | VKM |
| 631 | KBSC | KAPITAN BOEV SHIPPING CO LTD. | | | SCAC3 |
| 632 | KBSD | KBS TRUCKING LTD | | | SCAC4 |
| 633 | KBSE | K B S ENTERPRISES INC | | | SCAC4 |
| 634 | KBSG | KOUNTRY BOYS SAUSAGE | | | SCAC4 |
| 635 | KBSI | K & B SERVICES INC | | | SCAC3 |
| 636 | KBSK | KOMROWSK | | | SCAC4 |
| 637 | KBSL | K B S LEASING INC | | | SCAC3 |
| 638 | KBSL | KILBACK STOCK FARM LTD | | | SCAC4 |
| 639 | KBSN | K B S INC | | | SCAC3 |
| 640 | KBSN | KBS INC | | | SCAC4 |
| 641 | KBSP | KLEIN BROS TRANSPORTATION | | | SCAC3 |
| 642 | KBSR | Kankakee, Beaverville and Southern R.R. Co. | added 4/1978; 1/1980-7/2005 | | NAKINA |
| 643 | KBSR | Kankakee, Beaverville and Southern R.R. Co. | added 4/78; 1/80-7/2000 | | NRHS |
| 644 | KBSR | KANKAKEE, BEAVERVILLE & SOUTHERN RAILROAD | | | PWRC |
| 645 | KBSR | Kankakee, Beaverville and Southern Railroad | | | RSRV |
| 646 | KBSR | KANKAKEE BEAVERVILLE AND SOUTHERN R | | | SCAC3 |
| 647 | KBSR | Kankakee, Beaverville and Southern R.R. Co. | | USA | TRAFFIC |
| 648 | KBSS | KB SERVICES LLC | | | SCAC4 |
| 649 | KBST | KREBS TRUCKING INC | | | SCAC4 |
| 650 | KBSU | K-BOX SOLUTION | | K | BIC |
| 651 | KBSV | KOPENS BUS SERVICE | | | SCAC3 |
| 652 | KBSV | KING, BRIAN SERVICES | | | SCAC4 |
| 653 | KBSZ | KANKAKEE, BEAVERVILLE & SOUTHERN RAILROAD | | | PWRC |
| 654 | KBSZ | Kankakee, Beaverville and Southern Railroad | | | RSRV |
| 655 | KBSZ | KANKAKEE BEAVERVILLE AND SOUTHERN R | | | SCAC4 |
| 656 | KBTA | K-B TRANSPORT INC | | | SCAC3 |
| 657 | KBTA | KELLY, BRANDON TRUCKING LLC | | | SCAC4 |
| 658 | KBTE | KENLEY, BOB TRUCKING INC | | | SCAC4 |
| 659 | KBTF | K & B TRANSFER & STORAGE | | | SCAC3 |
| 660 | KBTF | KENTWOOD BRICK & TILE MFG | | | SCAC4 |
| 661 | KBTG | KIRBY TRUCKING INC | | | SCAC3 |
| 662 | KBTH | KING BROTHERS TRANSPORT LLC | | | SCAC4 |
| 663 | KBTI | K & B TRANSIT INC | | | SCAC3 |
| 664 | KBTI | K & B LOGISTIC INC | | | SCAC4 |
| 665 | KBTJ | KLUTH, BRENT TRUCKING | | | SCAC4 |
| 666 | KBTK | K B TRUCKING | | | SCAC3 |
| 667 | KBTK | KB TRUCKING LLC | | | SCAC4 |
| 668 | KBTL | KURTZ, BRIAN TRUCKING LIMITED | | | SCAC3 |
| 669 | KBTL | KURTZ, BRIAN TRUCKING LIMITED | | | SCAC4 |
| 670 | KBTM | K & B TRUCKING INC | | | SCAC4 |
| 671 | KBTO | K & B TRANSPORTATION INC | | | SCAC3 |
| 672 | KBTO | K & B TRANSPORTATION INC | | | SCAC4 |
| 673 | KBTP | K-B TRANSPORT INC | | | SCAC3 |
| 674 | KBTP | K & B TRANSPORT INC OF GEORGIA | | | SCAC4 |
| 675 | KBTQ | KUBOTA T TRUCKING CO | | | SCAC3 |
| 676 | KBTR | K B TRANSPORTATION INC | | | SCAC4 |
| 677 | KBTS | K B TRANSPORT INC | | | SCAC4 |
| 678 | KBTV | K B TRUCKING (WILLIAM K BATTENFIELD | | | SCAC3 |
| 679 | KBTW | KB TRUCKING | | | SCAC3 |
| 680 | KBTW | KB TRUCKING | | | SCAC4 |
| 681 | KBUI | KG BUILDING | | | SCAC4 |
| 682 | KBUK | K & B TRUCKING | | | SCAC3 |
| 683 | KBUS | KAMMES BUS SERVICE INC | | | SCAC3 |
| 684 | KBV | Kustbevakningen | Callsign: Swecoast, | S | AVCODES |
| 685 | KBV | General Tullstryrelsen | Callsign: Swecoast, | S | AVCODES |
| 686 | KBV | Kustbevakningen | | | ICAO1 |
| 687 | KBWQ | KERSEY BROOKS AND WHITE DELIVERY SE | | | SCAC3 |
| 688 | KBWT | KLECZ, B W TRANSPORT | | | SCAC3 |
| 689 | KBWT | KUBI WEST | | | SCAC4 |
| 690 | KBX | IBEX – Usługi Lotnicze Sp. z o.o | Callsign: Skybex, | PL | AVCODES |
| 691 | KBXC | KB TRANSPORT CORP | | | SCAC4 |
| 692 | KBXI | KIRST, BOB TRANSPORT INC | | | SCAC4 |
| 693 | KBXN | KORABI TRANS INC | | | SCAC4 |
| 694 | KBZ | Air KBZ Limited | IATA: K7, Callsign: Jade Air, | MYA | AVCODES |
| 695 | KC | Kiwi Travel International Airlines | ICAO: KIC, Callsign: Kaytac, Ceased operations | NZ | AVCODES |
| 696 | KC | Carpathian Air Transport Ltd. | ICAO: CPP, Callsign: Carpatian, Designator changed to KC | H | AVCODES |
| 697 | KC | Carpathian Air Transport Ltd. | ICAO: CPP, Callsign: Carpatian, Designator KC recalled by IATA. Designator changed from KC* | H | AVCODES |
| 698 | KC | Cargoair New Zealand Ltd. | Designator KC recalled by IATA | NZ | AVCODES |
| 699 | KC | Cameroons Air Transport LTd. | | CAM | AVCODES |
| 700 | KC | Trans Atlantic Airlines | | USA | AVCODES |
