| 1 | KX | Cayman Airways Limited | ICAO: CAY, Callsign: Cayman, IATA Prefix: 378, | CAY | AVCODES |
| 2 | KXA | Jiangxi Express Commuter Aviation Co., Ltd. | | PRC | AVCODES |
| 3 | KXCI | KEYSTONE TRANSPORT COMPANY INC | | | SCAC4 |
| 4 | KXEI | KEN-X EXPRESS INC | | | SCAC3 |
| 5 | KXEI | K-LINE EXPRESS INC | | | SCAC4 |
| 6 | KXHR | Knoxville & Holston River R.R. Co., Inc. | added 10/1998; 7/2000-7/2005 | | NAKINA |
| 7 | KXHR | Knoxville & Holston River R.R. Co., Inc. | added 10/98; 7/2000 | | NRHS |
| 8 | KXHR | KNOXVILLE & HOLSTON RIVER RAILROAD CO., INC. | | | PWRC |
| 9 | KXHR | Knoxville and Holston River Railroad | | | RSRV |
| 10 | KXHR | KNOXVILLE & HOLSTON RIVER RAILROAD | | | SCAC4 |
| 11 | KXJV | KNOX, JOHN VILLAGE TRANSPORTATION | | | SCAC3 |
| 12 | KXLC | KXL CARRIERS INC | | | SCAC4 |
| 13 | KXLG | KONIX LOGISTICS LLC | | | SCAC4 |
| 14 | KXP | M Jets International Sdn Bhd t/a Kargo Xpress | IATA: WW, Callsign: Xpress Kargo, IATA Prefix: 313, Name changed from M Jets International Sdn Bhd t/a Love Fly. | MAL | AVCODES |
| 15 | KXPC | KOKOS XPRESS INC | | | SCAC4 |
| 16 | KXPI | KELLY EXPRESS INC | | | SCAC4 |
| 17 | KXPR | KINGS EXPRESS | | | SCAC3 |
| 18 | KXPR | KINGS EXPRESS | | | SCAC4 |
| 19 | KXTI | KRESS XPRESS TRANSPORTATION INC | | | SCAC4 |
| 20 | KXTP | KX TRANSPORT INC | | | SCAC4 |
| 21 | KXTQ | KEIZER TRAILER SALES INC | | | SCAC4 |
| 22 | KXTU | KAWASAKI KISEN KAISHA LTD - K LINE | | J | BIC |
| 23 | KXTU | KAWASAKI KISEN KAISHA LTD | | | SCAC4 |
