| 1 | FS | Missionary Aviation Fellowship | Name changed to Mission Aviation Fellowship. Formerly Arnhern Land Community Airlines Pty. Ltd. | AUS | AVCODES |
| 2 | FS | Servicios de Transportes Aéreos Fueguinos, S.A. | ICAO: STU, Callsign: Fueguino, IATA Prefix: 278, Ceased operations 2005. Designator FS* reinstated by IATA | RA | AVCODES |
| 3 | FS | Field Aircraft Services Ltd. | | GB | AVCODES |
| 4 | FS | Field Aircraft Services Ltd. | ICAO: FAS, Callsign: Fieldair, | GB | AVCODES |
| 5 | FS | Mission Aviation Fellowship | Name changed from Missionary Aviation Fellowship. Formerly Arnhern Land Community Airlines Pty. Ltd. | AUS | AVCODES |
| 6 | FS | Itali Airlines s.r.l. | ICAO: ACL, Callsign: Itali, Name changed from Transporti Aerei Italiani S.r.l. ICAO designator changed from ACO | I | AVCODES |
| 7 | FS | Syphax Airlines | ICAO: SYA, Callsign: Syphax, IATA Prefix: 393, Ceased operations on 30 July 2015. Founded ijn 2011. Commenced operations on 21 April 2012. | TN | AVCODES |
| 8 | FS | flyGlobal Charter Sdn Bhd | ICAO: FGG, Callsign: Bluefinch, Ceased operations in November 2018. | MAL | AVCODES |
| 9 | FS | M/S Air Falcon (Pvt) Ltd. | ICAO: FPK, Callsign: Feather, IATA Prefix: 785, | PK | AVCODES |
| 10 | FS | flyr AS | ICAO: FOX, Callsign: Greenstar, Ceased operations on 31 Janaury 2023. | N | AVCODES |
| 11 | FS | | | I | TRAFFIC |
| 12 | FS&W | Fort Smith & Western Ry. Co. | 8/1920-7/1936 | | NAKINA |
| 13 | FS&W | FT. SMITH & WESTERN RWY. | | | PWRC |
| 14 | FSA | Foster Aviation | Callsign: Foster-Air, | USA | AVCODES |
| 15 | FSA | Foster Aviation | | | ICAO1 |
| 16 | FSAB | FICAL SALES INC | | | SCAC3 |
| 17 | FSAC | FREIGHT STATION ACCOUNTING CODE TAR | | | SCAC3 |
| 18 | FSAC | FLETES Y ACARREOS DE REYNOSA S A | | | SCAC4 |
| 19 | FSAF | FUNDY XPRESS TRANSPORT LIMITED | | | SCAC4 |
| 20 | FSAG | FOSTER SHIPPING AGENCY | | | SCAC3 |
| 21 | FSAG | FSA GR | | | SCAC4 |
| 22 | FSAH | FULL STEAM AHEAD | | | SCAC4 |
| 23 | FSAJ | FRANKSON & SON TRUCKING | | | SCAC4 |
| 24 | FSAK | FR EIGHT (FR8) | | | SCAC4 |
| 25 | FSAN | F S CARGO INC | | | SCAC4 |
| 26 | FSAO | FISHER AUTO SALES TRANSPORTATION IN | | | SCAC3 |
| 27 | FSAO | FISHER AUTO SALES TRANSPORTATION IN | | | SCAC4 |
| 28 | FSAP | FOUR STAR TRANSPORTATION INC | | | SCAC3 |
| 29 | FSAP | FRESHLANE TRANSIT INC | | | SCAC4 |
| 30 | FSAQ | FRANCIS SURACE TRANSPORTATION INC | | | SCAC4 |
| 31 | FSAR | FIVE STAR TRUCKING INC | | | SCAC4 |
| 32 | FSAS | FIVE STAR FREIGHT SERVICES | | | SCAC4 |
| 33 | FSAT | FIRST STATE TRUCKING INC | | | SCAC4 |
| 34 | FSAU | FAREDEAL SHIPPING AGENCIES (MUM) PVT LTD | | IND | BIC |
| 35 | FSAV | FIVE STAR TRANSPORTATION | | | SCAC4 |
| 36 | FSAW | FOUR (4) STAR TRANSPORT LTD | | | SCAC4 |
| 37 | FSB | FSB Flugservice & Development GmbH | Callsign: Seabird, | D | AVCODES |
| 38 | FSB | Flight Services International Ltd. | Callsign: Flint, | GB | AVCODES |
| 39 | FSB | FSB Flugservice & Development | | | ICAO1 |
| 40 | FSB | Frederikshavn - Skagen Banen | 1890 - 1924 | DK | jernbanen.dk |
| 41 | FSB | Frederikshavn - Skagen Banen | 1890 - 1924 | DK | TRAFFIC |
| 42 | FSBB | FOUR (4) S TRANSPORT LLC | | | SCAC4 |
| 43 | FSBE | FIVE SIX FIVE TWO TWO ONE ZERO (565 | | | SCAC4 |
| 44 | FSBF | FOUILLARD STEEL SUPPLIES LTD | | | SCAC4 |
| 45 | FSBK | FATHER SAMS BAKERY | | | SCAC4 |
| 46 | FSBT | FOUR-STAR (4-STAR) BULK TRANSPORT I | | | SCAC4 |
| 47 | FSC | Four Star Aviation | IATA: HK, Callsign: Four Star, IATA Prefix: 861, Designator HK reinstated by IATA | VI | AVCODES |
| 48 | FSC | Four Star Aviation | Callsign: Four Star, Designator HK recalled by IATA | VI | AVCODES |
| 49 | FSC | Four Star Cargo | IATA: HK | | ICAO1 |
| 50 | FSCA | FEDERAL SERVICES COMPANY | | | SCAC3 |
| 51 | FSCB | FARM SERVICE COMPANY | | | SCAC4 |
| 52 | FSCC | F S C CORP | | | SCAC3 |
| 53 | FSCD | FIVE STAR CONSOLIDATION SERVICE | | | SCAC3 |
| 54 | FSCD | FEEDING SYSTEMS CANADA | | | SCAC4 |
| 55 | FSCE | FARMERS SEAFOOD COMPANY INC | | | SCAC4 |
| 56 | FSCH | FOESCH TRANSFER LINE | | | SCAC3 |
| 57 | FSCH | FRISCHKORN ASSOCIATES INC | | | SCAC4 |
| 58 | FSCHO | Fischle & Schlienz Omnibusverkehr GmbH & Co. KG | | D | TRAFFIC |
| 59 | FSCI | FLOYDS OF SOUTH CAROLINA INC | | | SCAC3 |
| 60 | FSCJ | FIVE STAR COACH INC | | | SCAC3 |
| 61 | FSCJ | FISCHER TRUCKING | | | SCAC4 |
| 62 | FSCK | FISCHER TRUCKING INC | | | SCAC4 |
| 63 | FSCL | FIRST CLASS LIMOUSINE SERVICE INC | | | SCAC3 |
| 64 | FSCL | FLORENCIA SHIPPING COMPANY LIMITED | | | SCAC4 |
| 65 | FSCN | FAMILY SWEETS CANDY COMPANY INC | | | SCAC3 |
| 66 | FSCO | FARM SUPPLY CO | | | SCAC3 |
| 67 | FSCO | FARM SUPPLY CO | | | SCAC4 |
| 68 | FSCP | FOUR STATES TRANSPORTATION COMPANY | | | SCAC3 |
| 69 | FSCQ | FIRST STEAMSHIP CORP LTD TAIWAN | | | SCAC3 |
| 70 | FSCR | FIRST COURIER | | | SCAC3 |
| 71 | FSCS | FASCO CONTROLS CORP | | | SCAC3 |
| 72 | FSCT | FIRST CLASS TRANSPORT (1ST CLASS TR | | | SCAC3 |
| 73 | FSCU | FLORENS ASSET MANAGEMENT COMPANY LIMITED | | HK | BIC |
| 74 | FSCV | FIRST SCOTTS VALLEY INC | | | SCAC3 |
| 75 | FSCV | FARM SUPPLY DISTRIBUTORS INC | | | SCAC4 |
| 76 | FSCW | FIRST SHIPCO INC. | | | SCAC3 |
| 77 | FSCW | FLETES SANTA LUCIA SA DE CV | | | SCAC4 |
| 78 | FSCX | Frank Mitacek Railway Service | added 1/1983; eliminated 1/1989 | | NAKINA |
| 79 | FSCX | Ferro Standard Corp. | added 10/1966; 10/1966; eliminated 10/1968 | | NAKINA |
| 80 | FSCX | Freeport Sulphur Co. | 7/1930-4/1947; added 7/1958; eliminated 10/1958 | | NAKINA |
| 81 | FSCX | Freeport Sulphur Co. | 4/38; added 7/58; eliminated 10/58 | | NRHS |
| 82 | FSCX | Ferro Standard Corp. | added 10/66; 10/66; eliminated 10/68 | | NRHS |
| 83 | FSCX | Frank Mitacek Railway Service | added 1/83; eliminated 1/89 | | NRHS |
| 84 | FSCX | *FREEPORT SULPHUR CO. | | | PWRC |
| 85 | FSCX | *FERRO STANDARD CORP. | | | PWRC |
| 86 | FSCX | *FRANK MITACEK RAILWAY SERVICE | | | PWRC |
| 87 | FSCX | Frank Mitacek Railway Service | | | RSRV |
| 88 | FSCY | FORESHEW, CAREY TRUCKING | | | SCAC3 |
| 89 | FSD | EFS-Flugservice GmbH | Callsign: Flugservice, | D | AVCODES |
| 90 | FSD | EFS-Flugservice | | | ICAO1 |
| 91 | FSDA | FRONTIER SOUTH (DEDICATED DIVISION) | | | SCAC4 |
| 92 | FSDC | FREIGHT SOLUTIONS DIRECT LLC | | | SCAC4 |
| 93 | FSDE | FLEXCOAH SA DE CV | | | SCAC4 |
| 94 | FSDF | FOSTER, S D TRUCKING | | | SCAC4 |
| 95 | FSDI | FREIGHTSIDE INC | | | SCAC3 |
| 96 | FSDI | FONTASY SIGN & DISPLAY INC | | | SCAC4 |
| 97 | FSDK | FRISARDS TRUCKING CO INC | | | SCAC4 |
| 98 | FSDL | FOSTER SALES & DELIVERY INC | | | SCAC4 |
| 99 | FSDQ | FRASIER DEDICATED SERVICES INC | | | SCAC4 |
| 100 | FSDR | FRIONET S DE RL | | | SCAC4 |
