| 1 | KLS | Aerolynx | Callsign: Caracal, | KS | AVCODES |
| 2 | KLS | Kal Star Aviation, PT. | IATA: KD, Callsign: Kalstar, Ceased operations on 30 November 2017. | RI | AVCODES |
| 3 | KLS | Kalamazoo, Lake Shore & Chicago Ry. Co. | 8/1920-7/1923 | | NAKINA |
| 4 | KLS | KALAMAZOO, LAKE SHORE & CHICAGO RAILWAY CO. | | | PWRC |
| 5 | KLSA | KLS AIR EXPRESS INC | | | SCAC4 |
| 6 | KLSB | KOLIAS BROS TRUCKING | | | SCAC3 |
| 7 | KLSC | Kalamazoo, Lake Shore & Chicago Ry. | 1/1994-7/2005 | | NAKINA |
| 8 | KLSC | Kalamazoo, Lake Shore & Chicago Ry. | 1/94-7/2000 | | NRHS |
| 9 | KLSC | KALAMAZOO, LAKE SHORE & CHICAGO RAILWAY CO. | | | PWRC |
| 10 | KLSC | Kalamazoo, Lake Shore and Chicago Railway | | | RSRV |
| 11 | KLSC | LAKE SHORE & CHICAGO RAILWAY | | | SCAC3 |
| 12 | KLSE | KELLY, S E | | | SCAC3 |
| 13 | KLSF | KELSEY FARMS | | | SCAC3 |
| 14 | KLSF | KALER & SONS LOGISTICS | | | SCAC4 |
| 15 | KLSH | K & L SHIPPERS INC | | | SCAC4 |
| 16 | KLSI | KLS TRUCKING INC | | | SCAC4 |
| 17 | KLSL | KENT LINE SALES LIMITED | | | SCAC4 |
| 18 | KLSM | KEY LOGISTICS SOLUTIONS LLC (FLATBE | | | SCAC4 |
| 19 | KLSO | KATZ, L & SONS TRUCKING INC | | | SCAC3 |
| 20 | KLSO | KELSO E N E | | | SCAC4 |
| 21 | KLSP | KEYSTONE LIMOUSINE SERVICE INC | | | SCAC3 |
| 22 | KLSP | KALWAY SPECIALIZED TRANSPORT LTD | | | SCAC4 |
| 23 | KLSQ | KLIMAS PETROLEUM HAULING | | | SCAC3 |
| 24 | KLSS | KLS EXPRESS INC | | | SCAC3 |
| 25 | KLSS | KLASSEN, P CUSTOM FABRICATING | | | SCAC4 |
| 26 | KLST | KISSIMMEE LOGISTIC SERVICES INC | | | SCAC4 |
| 27 | KLSV | KING LIMOUSINE SERVICE INC | | | SCAC3 |
| 28 | KLSV | KENCO TRANSPORTATION | | | SCAC4 |
| 29 | KLSW | KLASSEN, WALTER FX | | | SCAC4 |
| 30 | KLSX | Weather Shield MFG, Inc. | added 1/2008 | | NAKINA |
| 31 | KLSX | Kerford Limestone Co. | added 7/1980; eliminated 10/1984 | | NAKINA |
| 32 | KLSX | Kerford Limestone Co. | added 7/80; eliminated 10/84 | | NRHS |
| 33 | KLSX | *KERFORD LIMESTONE CO. | | | PWRC |
| 34 | KLSX | +WEATHER SHIELD MFG., INC. | | | PWRC |
| 35 | KLSX | Kerford Limestone | | | RSRV |
| 36 | KLSX | WEATHER SHIELD MFG., INC. | | | SCAC4 |
| 37 | KLSY | KELSEY, THOMAS | | | SCAC3 |
