| 1 | FK | Keewatin Air Ltd. | ICAO: KEW, Callsign: Blizzard, Designator FK* recalled by IATA. IATA designator changed from 6K. Founded in 1998. in 1998. | CDN | AVCODES |
| 2 | FK | Flamenco Airways, Inc. | ICAO: WAF, Designator FK recalled by IATA | PRI | AVCODES |
| 3 | FK | Africa West | ICAO: WTA, Callsign: West Togo, IATA Prefix: 858, Designator FK recalled by IATA. IATA Desginator changed from FK*. Designator 3L* recalled by IATA | TG | AVCODES |
| 4 | FK | Africa West | ICAO: WTA, Callsign: West Togo, IATA Prefix: 858, IATA Desginator changed to FK. Designator 3L* recalled by IATA | TG | AVCODES |
| 5 | FK | Europe Falcon Service | ICAO: EFS, Designator FK recalled by IATA | F | AVCODES |
| 6 | FK | Kelowna Flightcraft Air Charter Ltd. | ICAO: KFA, Callsign: Flightcraft, IATA Prefix: 758, IATA designator changed from KW*. Designator KW* reinstated by IATA | CDN | AVCODES |
| 7 | FK | ? (Frankfurt-Königsteinek Eisenbahn) | | D | TRAFFIC |
| 8 | FKAR | FICK, ART RECYCLING INC | | | SCAC3 |
| 9 | FKAR | FARMINGTON TRUCKING INCORPORATED | | | SCAC4 |
| 10 | FKBT | FRANKIE B TRUCKING | | | SCAC3 |
| 11 | FKCC | FJK LOGISTICS LTD | | | SCAC4 |
| 12 | FKCH | FRANKLIN COACH CORP | | | SCAC3 |
| 13 | FKCI | FOUR (4) K CARTAGE INC | | | SCAC4 |
| 14 | FKCL | FUKOKU KONPO CO LTD | | | SCAC3 |
| 15 | FKCO | FINELLI-KIRSCHBAUM TRUCKING CORP | | | SCAC3 |
| 16 | FKCQ | FAIRBURN, KENNETH C | | | SCAC3 |
| 17 | FKCT | FROST, KENT CANYONLAND TOURS | | | SCAC3 |
| 18 | FKCT | FITZGERALD, GLENN TRUCKING LTD | | | SCAC4 |
| 19 | FKCX | Farmers Cooperative Creamery Co. (North Western Refrigerator Line Co.) | 7/1935 | | NAKINA |
| 20 | FKDN | FAK INC | | | SCAC4 |
| 21 | FKDS | FEIKEN, DENNIS | | | SCAC4 |
| 22 | FKDV | FRICK, DAVID G | | | SCAC3 |
| 23 | FKE | Frankfurt-Königsteiner Eisenbahn AG | Königstein (HLB-Gruppe) | D | privat-bahn.de |
| 24 | FKE | Frankfurt-Königsteiner Eisenbahn AG | | D | TRAFFIC |
| 25 | FKED | FREDERICK, EDWARD L | | | SCAC3 |
| 26 | FKEE | FIVE (5) K EXPRESS | | | SCAC4 |
| 27 | FKEH | FRIESEN, KENNETH | | | SCAC4 |
| 28 | FKEL | FRISK FARMS | | | SCAC3 |
| 29 | FKEP | F & K ENTERPRISES | | | SCAC3 |
| 30 | FKEP | FRITZEN TRUCKING INC | | | SCAC4 |
| 31 | FKER | FASTREK EXPRESS | | | SCAC4 |
| 32 | FKEV | FOUR (4) KENTERPRISES | | | SCAC4 |
| 33 | FKFS | FALKOWSKI FUEL SERVICES INC | | | SCAC4 |
| 34 | FKGC | FREIGHT KING LLC | | | SCAC4 |
| 35 | FKGE | FKG ENTERPRISE | | | SCAC4 |
| 36 | FKGH | FLECK, G H & SONS LTD | | | SCAC4 |
| 37 | FKGJK | MÁV FKG Felépítménykarbantartó és Gépjavító Kft. | | HU | VKM |
| 38 | FKGL | FREELS TRUCKING LLC | | | SCAC4 |
| 39 | FKHQ | FIKSE, HENRY | | | SCAC3 |
| 40 | FKI | Flm Aviation Mohrdieck GmbH & Co. KG | Callsign: Kiel Air, | D | AVCODES |
| 41 | FKI | FLM Aviation Mohrdieck | | | ICAO1 |
| 42 | FKIC | FLYING K INC | | | SCAC4 |
| 43 | FKIN | FRANKLIN INTERNATIONAL INC (CORPORA | | | SCAC3 |
| 44 | FKIN | FAK LOGISTICS, INC. | | | SCAC4 |
| 45 | FKKU | DALKOMHOLOD JSC | | RUS | BIC |
| 46 | FKKU | FUJITRANS ASIA PTE LTD | | | SCAC4 |
| 47 | FKKX | Farmers Co-operative Creamery Co. (North Western Refrigerator Line Co.) | 7/1935 | | NAKINA |
| 48 | FKL | Kelner Airways Ltd, V. | Callsign: Kelner, Name changed to V. Kelner Pilatus Center, Inc. | CDN | AVCODES |
| 49 | FKL | V. Kelner Pilatus Center, Inc. | Callsign: Kelner, Name changed to Levaero Aviation in May 2015. Name changed from Kelner Airways Ltd, V. | CDN | AVCODES |
| 50 | FKL | Levaero Aviation | Name changed from V. Kelner Pilatus Center, Inc. in May 2015. Name changed from Kelner Airways Ltd, V. | CDN | AVCODES |
| 51 | FKL | Kelner Airways | | | ICAO1 |
| 52 | FKLA | FOULK, L A CO | | | SCAC3 |
| 53 | FKLC | FRANKLIN CORPORATION | | | SCAC3 |
| 54 | FKLC | FRANKLIN LOGISTICS COMPANY LLC | | | SCAC4 |
| 55 | FKLD | FRANK, LINDSEY | | | SCAC4 |
| 56 | FKLE | FORKLIFT ENTERPRISES INC | | | SCAC3 |
| 57 | FKLE | FORKLIFT ENTERPRISES INC | | | SCAC4 |
| 58 | FKLG | FICKLING CARTAGE AND STORAGE | | | SCAC3 |
| 59 | FKLI | FRANKLIN COMPANY, THE | | | SCAC3 |
| 60 | FKLN | FRANKLIN EXPRESS | | | SCAC3 |
| 61 | FKLO | FINKE LOGGING COMPANY INCORPORATED | | | SCAC3 |
| 62 | FKLT | FRANKLIN TRANSPORTATION CORP | | | SCAC4 |
| 63 | FKMS | FAIRBANKS MOVING & STORAGE INC | | | SCAC4 |
| 64 | FKMT | FRANKLIN METAL TRADING CORPORATION | | | SCAC4 |
| 65 | FKMV | FRANK MOBILITY SYSTEMS INC | | | SCAC4 |
| 66 | FKNC | FRANKLIN CHARTERS INC | | | SCAC3 |
| 67 | FKNP | FRANKLIN TRANSPORTATION | | | SCAC4 |
| 68 | FKNQ | FRANKLIN, CARY C | | | SCAC3 |
| 69 | FKOC | FOLK OIL CO INC | | | SCAC4 |
| 70 | FKRC | FRANKLIN RODEO COMPANY LTD | | | SCAC4 |
| 71 | FKRD | FLYING K RANCH LTD | | | SCAC4 |
| 72 | FKRJ | FRANKS, R J TRANSPORT LTD | | | SCAC3 |
| 73 | FKRN | FLICK, RON TRUCKING INC | | | SCAC3 |
| 74 | FKRR | FAULKNER TRUCKING | | | SCAC4 |
| 75 | FKRS | F & K ROCK & SAND INC | | | SCAC3 |
| 76 | FKRX | The Flintkote Co. of Canada Ltd. | 4/1970; eliminated 10/1971 | | NAKINA |
| 77 | FKRX | Colas Roads, Ltd. (Flintkote Co. of Canada Ltd.) | 10/1966 | | NAKINA |
| 78 | FKRX | The Flintkote Co. of Canada Ltd. | 1/1945-7/1965 | | NAKINA |
| 79 | FKRX | Colas Roads, Ltd. | 7/1935; 4/1938-1/1943 | | NAKINA |
| 80 | FKRX | Flintkote Roads, Ltd. (Colas Roads, Ltd.) | 7/1932-7/1935 | | NAKINA |
| 81 | FKRX | Flintkote Roads, Ltd. | 7/1930 | | NAKINA |
| 82 | FKRX | Flintkote Roads, Ltd. (Colas Roads, Ltd.) | Apr-38 | | NRHS |
| 83 | FKRX | Flintkote Co. of Canada Ltd. | 1/52-7/65 | | NRHS |
| 84 | FKRX | Colas Roads, Ltd. (Flintkote Co. of Canada Ltd.) | Oct-66 | | NRHS |
| 85 | FKRX | The Flintkote Co. of Canada Ltd. | 4/70; eliminated 10/71 | | NRHS |
| 86 | FKRX | FLINTKOTE CO. OF CANADA [COLAS ROADS, LTD.; FLINTKOTE ROADS, LTD.] | | | PWRC |
| 87 | FKRX | FLINTKOTE COMPANY OF CANADA LTD | | | SCAC3 |
| 88 | FKS | Omega Air Holdings LLC dba Focus Air | IATA: F2, | USA | AVCODES |
| 89 | FKS | Focus Air | | | ICAO1 |
| 90 | FKS | Freundeskreis Selketalbahn e.V. | Alexisbad | D | privat-bahn.de |
| 91 | FKSE | FREERKSEN TRUCKING | | | SCAC3 |
| 92 | FKSE | FREERKSEN TRUCKING INC | | | SCAC4 |
| 93 | FKSF | FRANKIES FUEL LLC | | | SCAC4 |
| 94 | FKSL | FREDERICK, STEPHEN LOGISTICS INC | | | SCAC4 |
| 95 | FKSN | FRANKS & SON INC | | | SCAC3 |
| 96 | FKSO | FISKE TRUCKING COMPANY | | | SCAC3 |
| 97 | FKSO | FRANKS TRUCKING | | | SCAC4 |
| 98 | FKSP | FRANKLIN SPECIALTY TRANSPORT INC | | | SCAC4 |
| 99 | FKSQ | FRANKS DELIVERY SERVICE | | | SCAC3 |
| 100 | FKSS | FRANKS SPOTTING SERVICE | | | SCAC3 |
