| 5401 | KTPL | KANE 3PL LLC | | | SCAC4 |
| 5402 | KTPO | KNIGHT TRANSPORT INC | | | SCAC3 |
| 5403 | KTPO | KERSLAKE TRANSPORT LTD | | | SCAC4 |
| 5404 | KTPR | KET EXPRESS INC | | | SCAC4 |
| 5405 | KTPS | KEY TRANSPORTATION SERVICES INC | | | SCAC3 |
| 5406 | KTPW | KT POWER INC | | | SCAC4 |
| 5407 | KTQI | KTI LOGISTICS LLC | | | SCAC4 |
| 5408 | KTR | HT Helikoptertransport AB | Callsign: Copter Trans, Name changed to AB Flygtjanst F.J. Viklund | S | AVCODES |
| 5409 | KTR | AB Flygtjanst F.J. Viklund | Callsign: Copter Trans, Name changed from HT Helikoptertransport AB | S | AVCODES |
| 5410 | KTR | LLC SkyAviaTrans | AOC revoked by SAAU on 15 November 2019. | UA | AVCODES |
| 5411 | KTR | HT Helikoptertransport | | | ICAO1 |
| 5412 | KTR | Kendallville Terminal Ry. Co. | 7/2005 | | NAKINA |
| 5413 | KTR | KENDALLVILLE TERMINAL RAILWAY | | | PWRC |
| 5414 | KTR | Kendallville Terminal Railway | | | RSRV |
| 5415 | KTR | KENDALLVILLE TERMINAL RAILWAY CO | | | SCAC4 |
| 5416 | KTR | Kitakinki Tango Railway | | J | TRAFFIC |
| 5417 | KTRA | K-TRAN CORP | | | SCAC3 |
| 5418 | KTRA | KUNSMAN TRANSPORT LTD | | | SCAC4 |
| 5419 | KTRB | K OCEAN TRANSPORT LLC | | | SCAC4 |
| 5420 | KTRC | KERINS TRANSPORTATION CO INC | | | SCAC3 |
| 5421 | KTRD | KINGSERV TRADING SUPPLYING LTD | | | SCAC3 |
| 5422 | KTRH | KLIMCO TRANSPORT | | | SCAC4 |
| 5423 | KTRI | KAR-A-VAN TRANSFER INC | | | SCAC3 |
| 5424 | KTRK | KING TRUCKING CO, INC | | | SCAC3 |
| 5425 | KTRL | KELLER TRANSFER LINE, INC | | | SCAC3 |
| 5426 | KTRL | KELLER TRANSFER LINE INC | | | SCAC4 |
| 5427 | KTRM | KREUZIGER TRUCKING | | | SCAC4 |
| 5428 | KTRO | KOMNICK TRUCKING | | | SCAC3 |
| 5429 | KTRO | KC TRANSPORT | | | SCAC4 |
| 5430 | KTRP | KENIAS TRANSPORT LLC | | | SCAC4 |
| 5431 | KTRQ | KRENEK TRACTOR REPAIR | | | SCAC3 |
| 5432 | KTRQ | KONE TRANSPORT | | | SCAC4 |
| 5433 | KTRR | KINGDOM TRUCKING | | | SCAC4 |
| 5434 | KTRS | KING TRAVEL SERVICE | | | SCAC3 |
| 5435 | KTRT | KLB TRUCKING | | | SCAC4 |
| 5436 | KTRW | KEE TRANS INC | | | SCAC4 |
| 5437 | KTRY | KTI RECYCLING OF NEW ENGLAND INC | | | SCAC4 |
| 5438 | KTS | Kotlas Air Enterprises, Federal State Unitary Enterprise | Callsign: Kotair, Name changed to Transair-Gyrantiee, Aircompany, Ojs Company | RUS | AVCODES |
| 5439 | KTS | Kotlas Joint Civil Aviation Enterprise | Callsign: Kotlas Avia, | RUS | AVCODES |
| 5440 | KTS | Transair-Gyrantiee, Aircompany, OJS Company | Callsign: Kotair, Name changed from Kotlas Air Enterprises, Federal State Unitary Enterprise | RUS | AVCODES |
| 5441 | KTS | Transair-Gyraintiee | | | ICAO1 |
| 5442 | KTSB | KENTUCKY TRANSPORT SYSTEM INC | | | SCAC4 |
| 5443 | KTSC | KANE TRAFFIC SERVICES INC | | | SCAC4 |
| 5444 | KTSD | KOSTIUCK TRANSPORTATION & SERVICES | | | SCAC3 |
| 5445 | KTSD | KAHULUI TRUCKING & STORAGE INC | | | SCAC4 |
| 5446 | KTSE | KEY TRANSPORTATION SERVICE INC | | | SCAC3 |
| 5447 | KTSE | KTS | | | SCAC4 |
| 5448 | KTSF | KAMINO TRANSPORTATION SERVICES INC | | | SCAC4 |
| 5449 | KTSG | K T S LOGISTICS LLC | | | SCAC4 |
| 5450 | KTSH | KT SERVICES INC | | | SCAC4 |
| 5451 | KTSI | KROBLIN TRANSPORTATION SYSTEMS INC | | | SCAC3 |
| 5452 | KTSI | KELLES TRANSPORT SERVICE INC | | | SCAC4 |
| 5453 | KTSJ | KAJUN TREY SERVICE LLC | | | SCAC4 |
| 5454 | KTSK | KEITHS TRANSPORT SERVICE LIMITED LI | | | SCAC4 |
| 5455 | KTSL | KANO TRUCKING SERVICE LTD | | | SCAC3 |
| 5456 | KTSL | KTS HEAVY HAULING INC | | | SCAC4 |
| 5457 | KTSM | K TANKERING AND SHIPMANAGEMENT S A | | | SCAC4 |
| 5458 | KTSN | KTS INC | | | SCAC3 |
| 5459 | KTSO | KITSON TRANSPORT INC | | | SCAC4 |
| 5460 | KTSP | KIEFS TRANSFER SPECIALISTS & INC | | | SCAC3 |
| 5461 | KTSP | KING TRANSPORT SERVICES | | | SCAC4 |
| 5462 | KTSR | KOHLER TRANSPORT SERVICE INC | | | SCAC3 |
| 5463 | KTSR | KINNIN TRANSPORTATION SERVICES | | | SCAC4 |
| 5464 | KTSS | KELMAN TRANSPORTATION SERVICES INC | | | SCAC3 |
| 5465 | KTST | KTS TRUCK LINES INC | | | SCAC3 |
| 5466 | KTST | K & T SWITCHING SERVICE INC | | | SCAC4 |
| 5467 | KTSU | KTZ EXPRESS JSC | | KZ | BIC |
| 5468 | KTSU | JOINT STOCK COMPANY KAZTRANSSERVIC | | | SCAC4 |
| 5469 | KTSV | KOURIER TRANSPORT SERVICE | | | SCAC3 |
| 5470 | KTTA | K-TAHOE TRUCKING INC | | | SCAC4 |
| 5471 | KTTC | KETCHIKAN TRANSPORTATION CO | | | SCAC3 |
| 5472 | KTTE | KT 2008 | | | SCAC4 |
| 5473 | KTTF | KMIEC, TOM TRUCKING INC | | | SCAC4 |
| 5474 | KTTG | KELSEY TRAIL TRUCKING LTD | | | SCAC3 |
| 5475 | KTTG | K-T TRUCKING | | | SCAC4 |
| 5476 | KTTH | KWRL TRACTORS & TRUCKING | | | SCAC4 |
| 5477 | KTTJ | K & T TRANSPORT INC | | | SCAC4 |
| 5478 | KTTL | KITTRELL, DURWARD KENNETH | | | SCAC3 |
| 5479 | KTTN | KEETON TRUCKING CO INC | | | SCAC3 |
| 5480 | KTTN | KOTTEN ENTERPRISES LLC | | | SCAC4 |
| 5481 | KTTO | KITTO TRUCKING | | | SCAC3 |
| 5482 | KTTP | K T TRANSPORT INC | | | SCAC3 |
| 5483 | KTTP | K & T TRANSPORT LTD | | | SCAC4 |
| 5484 | KTTQ | KITTS TRUCKING | | | SCAC3 |
| 5485 | KTTR | KITA TRANSPORT | | | SCAC3 |
| 5486 | KTTU | KOTTA CONTAINER COMPANY LTD | | RUS | BIC |
| 5487 | KTTU | Krasnodar Tram and Trolleybus Administration | City: Krasnodar | RUS | TRAFFIC |
| 5488 | KTTV | KAPTANOGLU TANKERCILIK TIC A.S | | | SCAC4 |
| 5489 | KTTW | KITT WAREHOUSE & DIST INC | | | SCAC3 |
| 5490 | KTTW | KRUEGER TRUCKING TWO (2) LAZY TWO ( | | | SCAC4 |
| 5491 | KTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 5492 | KTTX | Trailer Train Co. | added 1/1964; 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 5493 | KTTX | Trailer Train Co. (FA flat cars equipped with tri-level automobile carrying superstructures with movable end sections of second, or second and third decks, furnished by member railroads. Cars are not equipped with hitches or bridge plates) | added 1/1964; 7/1965-10/1968 | | NAKINA |
| 5494 | KTTX | Trailer Train Co. (flat cars, equipped with hinged end tri-level auto racks furnished by participant railroads) | 4/1970-1/1980 | | NAKINA |
| 5495 | KTTX | Trailer Train Co./TTX Co. (standard deck flat cars with non-collapsable hitches, capable of handling any two trailers, with 36"" kingpin spacing, whose overall combined length does not exceed 90' — i.e., 2-45', 1-42' & 1-48', 1-40' & 1-48', etc. — between lift-on/lift-off facilities only) | 7/1985-7/2000 | | NAKINA |
| 5496 | KTTX | Trailer Train Co. | Jul-65 | | NRHS |
| 5497 | KTTX | Trailer Train Co. (FA flat cars equipped with tri-level automobile carrying superstructures with movable end sections of second, or second and third decks, furnished by member railroads. Cars are not equipped with hitches or bridge plates) | 10/66-10/68 | | NRHS |
| 5498 | KTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 5499 | KTTX | Trailer Train Co. (flat cars, equipped with hinged end tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 5500 | KTTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
