| 4601 | KRLK | KREILKAMP TRUCKING INC | | | SCAC4 |
| 4602 | KRLL | KERRY LIMOUSINE LTD | | | SCAC3 |
| 4603 | KRLL | KARL, LARRY M TRUCKING INC | | | SCAC4 |
| 4604 | KRLN | KARLIN NAVIGATION LTD | | | SCAC4 |
| 4605 | KRLQ | KTR LOGISTICS | | | SCAC4 |
| 4606 | KRLT | KARLS TRANSPORT INC | | | SCAC3 |
| 4607 | KRLT | KARLS TRANSPORT INC | | | SCAC4 |
| 4608 | KRLU | DP WORLD RAIL LOGISTICS PRIVATE LIMITED | | IND | BIC |
| 4609 | KRLV | KRALEVICH TRUCKING INC | | | SCAC4 |
| 4610 | KRLX | National Car Co. | 4/1947-1/1950 | | NAKINA |
| 4611 | KRLX | Kingan Refrigerator Line | 8/1920-1/1941 | | NAKINA |
| 4612 | KRLX | Kingan Refrigerator Line | Apr-38 | | NRHS |
| 4613 | KRLX | *KINGAN REFRIGERATOR LINE | | | PWRC |
| 4614 | KRLX | *NATIONAL CAR CO. | | | PWRC |
| 4615 | KRLX | KEYSTONE RAILCAR INC | | | SCAC4 |
| 4616 | KRM | Crimea Universal Avia | Callsign: Trans Universal, | UA | AVCODES |
| 4617 | KRM | Crimea Universal Avia | | | ICAO1 |
| 4618 | KRM | KENTUCKY RAILWAY MUSEUM | | | PWRC |
| 4619 | KRM | Krauss-Maffei | | D | TRAFFIC |
| 4620 | KRMD | KORMENDY TRUCKING | | | SCAC3 |
| 4621 | KRME | KRAMME, P E, INC | | | SCAC3 |
| 4622 | KRME | KRAMME | | | SCAC4 |
| 4623 | KRMK | KARMACK TRANSPORTATION INC | | | SCAC3 |
| 4624 | KRML | KERR MOTOR LINES, INC | | | SCAC3 |
| 4625 | KRML | Kreisbahn Mansfelder Land | Real: KML, Die Kreisbahn Mansfelder Land GmbH (KML) ist ein öffentliches Eisenbahninfrastruktur-[1] (EIU) und -verkehrsunternehmen (EVU). Als EIU betreibt es die Parkeisenbahn Vatterode. Als EVU fährt es im Auftrag der Nahverkehrsservice Sachsen-Anhalt im Personenverkehr auf der Bahnstrecke Klostermansfeld–Wippra. | D | TRAFFIC |
| 4626 | KRMQ | KRAMERTOWN CO INC | | | SCAC3 |
| 4627 | KRMR | KRAMER, GERALD L INC | | | SCAC3 |
| 4628 | KRMR | KRAMER SCULPTURES INC | | | SCAC4 |
| 4629 | KRMS | KRUKENKAMP MOVING & STORAGE INC | | | SCAC3 |
| 4630 | KRMS | KROEKER MACHINERY SALES LTD | | | SCAC4 |
| 4631 | KRMU | HANS-GEORG KRAMER MOBELTRANSPORTE | | D | BIC |
| 4632 | KRMV | KNIFE RIVER MATERIALS | | | SCAC4 |
| 4633 | KRMW | KRUMWIEDE | | | SCAC4 |
| 4634 | KRMX | Union Tank Car Co. | added 7/1961; 7/1965-4/1970; eliminated 7/1973 | | NAKINA |
| 4635 | KRMX | Kerr-McGee Oil Industries, Inc. | added 7/1956; 10/1957-4/1961; eliminated 7/1961 | | NAKINA |
| 4636 | KRMX | Kerr-McGee Oil Industries, Inc. | added 7/56; 10/57-4/61 | | NRHS |
| 4637 | KRMX | Union Tank Car Co. | 7/65-4/70; eliminated 7/73 | | NRHS |
| 4638 | KRMX | *KERR-MCGEE OIL INDUSTRIES, INC. (UNION TANK CAR CO.) | | | PWRC |
| 4639 | KRMX | *KERSHAW MANUFACTURING COMPANY, INC. | | | PWRC |
| 4640 | KRMX | KAWASA | | | SCAC4 |
| 4641 | KRN | Kaz Agros Avia | Callsign: Antol, | KZ | AVCODES |
| 4642 | KRN | Karinou Airlines | IATA: U5, Designator U5* recalled by IATA | RCA | AVCODES |
| 4643 | KRN | Karinou Airlines | Designator U5* recalled by IATA | RCA | AVCODES |
| 4644 | KRN | Kaz Agros Avia | | | ICAO1 |
| 4645 | KRNC | KEARNS CARTAGE INC | | | SCAC3 |
| 4646 | KRNE | KEARNEY TRUCKING COMPANY | | | SCAC3 |
| 4647 | KRNG | KRINGLER, HAROLD | | | SCAC3 |
| 4648 | KRNH | KRAMER & HOUSTON TOWING SERVICE INC | | | SCAC3 |
| 4649 | KRNI | KRIEGER, NORMAN INC | | | SCAC3 |
| 4650 | KRNM | KERNS & SONS MOVING & STORAGE INC | | | SCAC3 |
| 4651 | KRNN | KRUEGER TRANSPORT INC | | | SCAC4 |
| 4652 | KRNR | KERN TRUCKING | | | SCAC3 |
| 4653 | KRNR | KERN ENGINEERING | | | SCAC4 |
| 4654 | KRNS | KARNS, S T, TRANSPORTATION COMPANY | | | SCAC3 |
| 4655 | KRNT | KARAN TRUCKING INC | | | SCAC4 |
| 4656 | KRNV | KERN VALLEY TRUCKING | | | SCAC3 |
| 4657 | KRNW | KRESSER NATIONWIDE TRUCKLOAD SERVIC | | | SCAC3 |
| 4658 | KRO | Kroonk, Air Agency Ltd. | Callsign: Kroonk, | UA | AVCODES |
| 4659 | KRO | Aliblu Airways S.p.A. | IATA: KR, Callsign: Alibly, | I | AVCODES |
| 4660 | KRO | Kroonk Air Agency | | | ICAO1 |
| 4661 | KRO | Kronospan CR s.r.o. | | BG | VKM |
| 4662 | KROA | KARPETZ, RODNEY | | | SCAC4 |
| 4663 | KROB | KELLY, ROBERT | | | SCAC4 |
| 4664 | KROD | KROPF INDUSTRIAL INC | | | SCAC4 |
| 4665 | KROF | KRO-FLITE CARTAGE COMPANY | | | SCAC3 |
| 4666 | KROI | KRESTCO INC | | | SCAC3 |
| 4667 | KROISS | L. Kroiss GmbH & Co. KG | City: Rosenheim | D | TRAFFIC |
| 4668 | KROK | KROESCHEL, KENNETH | | | SCAC3 |
| 4669 | KRONO | Länstrafiken Kronoberg | | SE | VKM |
| 4670 | KRONR | SC KRONOSPAN ROMANIA SRL | | RO | VKM |
| 4671 | KROO | KROON SHIPPING CORPORATION | | | SCAC3 |
| 4672 | KROP | KROEGER PRECAST INC | | | SCAC3 |
| 4673 | KROP | KROPEINICKI BROS | | | SCAC4 |
| 4674 | KROR | KROGER CO | | | SCAC3 |
| 4675 | KROS | KROOSWYK TRUCKING & EXCAVATING INC | | | SCAC3 |
| 4676 | KROSNO | Miejskiej Komunikacji Samochodowej w Krośnie | | PL | TRAFFIC |
| 4677 | KROT | KARO TRANSPORTATION | | | SCAC3 |
| 4678 | KROT | Miejski Zakład Komunikacji w Krotoszynie | | PL | TRAFFIC |
| 4679 | KROU | KRONOCHEM LLC | | BY | BIC |
| 4680 | KROV | KROVITZ, E M, INC | | | SCAC3 |
| 4681 | KROW | KROW INDUSTRIES INC | | | SCAC3 |
| 4682 | KROY | KROY TRANSPORTATION CO | | | SCAC3 |
| 4683 | KRP | Carpatair, S.A. | IATA: V3, Callsign: Carpatair, ICAO designator changed form VEG, Name changed from Veg Air S.R.L. ICAO callsign changed from Vegflight | RO | AVCODES |
| 4684 | KRP | Carpatair | IATA: V3 | | ICAO1 |
| 4685 | KRPD | KENYON RACING PRODUCTS | | | SCAC4 |
| 4686 | KRPN | KARPINSKI TRUCKING | | | SCAC3 |
| 4687 | KRPN | KARPINSKI TRUCKING | | | SCAC4 |
| 4688 | KRPP | KROPP, J L TRUCKING INC | | | SCAC3 |
| 4689 | KRPQ | KR PACKAGING INC | | | SCAC4 |
| 4690 | KRPR | KARPER CHARLES W INC | | | SCAC3 |
| 4691 | KRPS | KRUPP SEESCHIFFAHRT GMBH | | | SCAC3 |
| 4692 | KRPU | JSC «KRASNOYARSK RIVER PORT» | | RUS | BIC |
| 4693 | KRPU | KARLANDER (AUSTRALIA) PTY., LTD | | | SCAC3 |
| 4694 | KRPX | Associated Electric Cooperative, Inc. | 1/1980 | | NAKINA |
| 4695 | KRPX | Associated Electric Cooperative, Inc. (captive service) | 1/1994 (not listed) | | NAKINA |
| 4696 | KRPX | Associated Electric Cooperative, Inc. | Jan-80 | | NRHS |
| 4697 | KRPX | Associated Electric Cooperative, Inc. (captive service) | Jan-94 | | NRHS |
| 4698 | KRPX | ASSOCIATED ELECTRIC COOPERATIVE, INC. | | | PWRC |
| 4699 | KRPX | Associated Electric Cooperative | | | RSRV |
| 4700 | KRR | Kiamichi R.R. Co., L.L.C. | added 10/1996; 7/2000-7/2005 | | NAKINA |
