| 6601 | FSSK | FORTRESS TRUCKING LTD | | | SCAC4 |
| 6602 | FSSM | FINESSE MARITIME CO LTD | | | SCAC3 |
| 6603 | FSSM | FREEWAY STEAMSHIP SA PANAMA | | | SCAC4 |
| 6604 | FSSN | FIVE SEVEN SIX NINE NINE SEVEN (576 | | | SCAC3 |
| 6605 | FSSN | FOSSE TRANSPORT | | | SCAC4 |
| 6606 | FSSP | FOUR (4) SSSS TRANSPORT | | | SCAC4 |
| 6607 | FSSQ | FREIGHT SOLUTION SERVICES INC | | | SCAC4 |
| 6608 | FSSR | FOUR SEASONS SERVICES INC | | | SCAC4 |
| 6609 | FSSS | FOUR S CO (4-S CO) | | | SCAC3 |
| 6610 | FSSS | FREIGHT SOLUTION SERVICES INC | | | SCAC4 |
| 6611 | FSST | FOSS TRUCKING | | | SCAC4 |
| 6612 | FSSU | FUGRO SUBSEA TECHNOLOGIES PTE LTD | | SGP | BIC |
| 6613 | FSSV | FENWICK SHIPPING SERVICES LTD. | | | SCAC3 |
| 6614 | FSSW | FOUR SEAS & SEVEN WINDS TRAVEL AGEN | | | SCAC3 |
| 6615 | FSSW | FRIENDSHIP SHIPPING SERVICES INC | | | SCAC4 |
| 6616 | FSSX | F.S. Transportation, LLC | added 10/2003; eliminated 4/2004; 7/2005 (not listed) | | NAKINA |
| 6617 | FSSX | F. S. TRANSPORTATION, LLC | | | PWRC |
| 6618 | FSSY | FIVE SEVEN SEVEN SIX EIGHT THREE ON | | | SCAC4 |
| 6619 | FST | Fast Air Ltda. | IATA: UD, Callsign: Faster, Designator UD recalled by IATA | RCH | AVCODES |
| 6620 | FST | Fast Air Ltda. | Callsign: Faster, Designator UD recalled by IATA | RCH | AVCODES |
| 6621 | FST | Aeros Ltd. | Callsign: Fast Track, ICAO Callsign changed from Glos | GB | AVCODES |
| 6622 | FST | Airtanker Services Ltd | ICAO designator changed to TOW | GB | AVCODES |
| 6623 | FST | Flight Support, Inc. | Callsign: Flightron, | USA | AVCODES |
| 6624 | FST | Aereos Limited | | | ICAO1 |
| 6625 | FST | Ferrocarriles Nacionales de Mexico | added 4/1996; 7/2000-7/2005 | | NAKINA |
| 6626 | FST | Ferrocarriles Nacionales de Mexico | added 4/96; 7/2000 | | NRHS |
| 6627 | FST | FERROCARRILES NACIONALES DE MEXICO | | | PWRC |
| 6628 | FST | Ferrocarriles Nacionales de Mexico | | | RSRV |
| 6629 | FSTB | FISCHER TRUCK & BUS SERVICE INC | | | SCAC3 |
| 6630 | FSTB | FOSTER, JOHN TRUCKING | | | SCAC4 |
| 6631 | FSTC | F & S TRANSIT COMPANY, INC | | | SCAC3 |
| 6632 | FSTD | F A S T INC | | | SCAC4 |
| 6633 | FSTE | FISTER VINCENT INC | | | SCAC3 |
| 6634 | FSTF | FOSTER FARMS | | | SCAC4 |
| 6635 | FSTG | FAST SPEAR TRUCKING | | | SCAC4 |
| 6636 | FSTH | FOGERSON TRUCKING | | | SCAC3 |
| 6637 | FSTH | FORSYTH MANUFACTURING LTD | | | SCAC4 |
| 6638 | FSTI | FOUR STAR TRANSPORT SERVICE INC | | | SCAC3 |
| 6639 | FSTI | FOSTER TRUCKING | | | SCAC4 |
| 6640 | FSTJ | FOSTER TRANSFER INC | | | SCAC3 |
| 6641 | FSTK | FAST TRACKS LLC | | | SCAC4 |
| 6642 | FSTL | FASTENAL COMPANY | | | SCAC4 |
| 6643 | FSTL | Fastline Freight | | GB | TRAFFIC |
| 6644 | FSTM | FORT SMITH TROLLEY MUSEUM | | | PWRC |
| 6645 | FSTM | FOSTER, NORMAN R | | | SCAC3 |
| 6646 | FSTM | FRASERS THIMBLE FARMS | | | SCAC4 |
| 6647 | FSTO | FREE SPIRIT TRANSPORT INC | | | SCAC3 |
| 6648 | FSTO | F S TOOL CORPORATION | | | SCAC4 |
| 6649 | FSTP | FIRST CHOICE TRANSPORT INC | | | SCAC3 |
| 6650 | FSTP | FIRST CHOICE TRANSPORT INC | | | SCAC4 |
| 6651 | FSTR | FOSTER TRUCKING | | | SCAC3 |
| 6652 | FSTT | F S TRUCKING | | | SCAC3 |
| 6653 | FSTT | FIVE STAR TRANSPORT INC | | | SCAC4 |
| 6654 | FSTU | FASTRAC INTERMODAL L.L.C. | | | PWRC |
| 6655 | FSTU | Fastrac Intermodal | | | RSRV |
| 6656 | FSTU | FLOPETROL - SCHLUMBERGER SERVICES | | | SCAC3 |
| 6657 | FSTU | FSTA TRUCKING INC | | | SCAC4 |
| 6658 | FSTV | F S T TRANSPORTATION INC | | | SCAC3 |
| 6659 | FSTV | FOUR (4) SEASONS TRANSPORTATION INC | | | SCAC4 |
| 6660 | FSTW | FASTWAY FOODS | | | SCAC3 |
| 6661 | FSTW | FAST WAY TRANSPORT | | | SCAC4 |
| 6662 | FSTX | Fuel Supply Trust | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 6663 | FSTX | Fuel Supply Trust | added 1/97; 7/2000 | | NRHS |
| 6664 | FSTX | FUEL SUPPLY TRUST | | | PWRC |
| 6665 | FSTX | FUEL SUPPLY TRUST | | | PWRC |
| 6666 | FSTX | Fuel Supply Trust | | | RSRV |
| 6667 | FSTY | FOUR STAR TRANSPORTATION CO | | | SCAC4 |
| 6668 | FSTZ | FASTRAC INTERMODAL L.L.C. | | | PWRC |
| 6669 | FSTZ | Fastrac Intermodal | | | RSRV |
| 6670 | FSTZ | FASTRAC INTERMODAL L L C | | | SCAC4 |
| 6671 | FSU | Flight Support Sweden | | S | AVCODES |
| 6672 | FSU | Fly Sky Airlines | Callsign: Ukraine Bird, | UA | AVCODES |
| 6673 | FSU | Flight Support Sweden | | | ICAO1 |
| 6674 | FSUD | Fort Street Union Depot Co. | 1/1975-7/2005 | | NAKINA |
| 6675 | FSUD | Fort Street Union Depot Co. | 1/75-7/2000 | | NRHS |
| 6676 | FSUD | FORT STREET UNION DEPOT CO. | | | PWRC |
| 6677 | FSUD | Fort Street Union Depot | | | RSRV |
| 6678 | FSUD | FLOTA SUARDIAZ VLISSINGERM OOST NL | | | SCAC3 |
| 6679 | FSUD | FLOTA SUARDIAZ VLISSINGERM OOST NL | | | SCAC4 |
| 6680 | FSUK | FOUR STAR TRUCKING (4 STAR TRUCKING | | | SCAC3 |
| 6681 | FSUN | FORSUN ENTERPRISES | | | SCAC3 |
| 6682 | FSUP | FARMERS SUPPLY & TRANSPORTATION | | | SCAC3 |
| 6683 | FSUP | FARMERS SUPPLY & TRANSPORTATION | | | SCAC4 |
| 6684 | FSUU | OY FINNISH STEVEDORES AB | | | SCAC3 |
| 6685 | FSV | KANSAS CITY SOUTHERN RAILWAY [FORT SMITH & VAN BUREN RY.] | | | PWRC |
| 6686 | FSVA | FEEDLOT SERVICE CO | | | SCAC4 |
| 6687 | FSVB | Fort Smith & Van Buren Ry. Co. | 1/1975-7/2005 | | NAKINA |
| 6688 | FSVB | Fort Smith & Van Buren Ry. Co. | 1/75-7/2000 | | NRHS |
| 6689 | FSVB | KANSAS CITY SOUTHERN RAILWAY [FORT SMITH & VAN BUREN RY.] | | | PWRC |
| 6690 | FSVB | Fort Smith and Van Buren Railway | | | RSRV |
| 6691 | FSVB | FORT SMITH AND VAN BUREN RAILWAY CO | | | SCAC3 |
| 6692 | FSVC | FLEET SERVICE COMPANY | | | SCAC3 |
| 6693 | FSVC | FARM SERVICE COOPERATIVE | | | SCAC4 |
| 6694 | FSVH | FLEET SERVICE INC | | | SCAC4 |
| 6695 | FSVI | FLITE SERVICES INC | | | SCAC3 |
| 6696 | FSVJ | Föreningen Sörmlands Veteranjärnväg | | SE | VKM |
| 6697 | FSVL | FOUR (4) STAR VENTURES LTD | | | SCAC4 |
| 6698 | FSVR | FRATE SAVERS INC | | | SCAC4 |
| 6699 | FSVS | FARM SERVICE & SUPPLIES INC | | | SCAC3 |
| 6700 | FSVT | FER SERVICE STATION INC | | | SCAC4 |
