| 1 | TH | Transmile Air Services Sdn. Bhd. | ICAO: TSE, Callsign: Transmile, IATA Prefix: 539, Name changed to Raya Airways Sdn. Bhd. d/b/a Raya Airways. IATA designator changed from TH* | MAL | AVCODES |
| 2 | TH | British Regional Airlines Limited | ICAO: BRT, Callsign: British, Name changed to British Airways CitiExpress Limited Merged with Brymon and British Airways Regional 31 March 2002. Formerly Manx Airlines (Europe) Ltd. | GB | AVCODES |
| 3 | TH | Thai Airways Co. Ltd. | ICAO: TAC, Callsign: Thai Air, Merged into Thai International | T | AVCODES |
| 4 | TH | LAR Transregional, Linhas Aerea Regionais, S.A. | ICAO: PDF, Designator TH recalled by IATA | P | AVCODES |
| 5 | TH | Transmile Air Services Sdn. Bhd. | ICAO: TSE, Callsign: Transmile, IATA designator changed to TH | MAL | AVCODES |
| 6 | TH | British Airways CitiExpress Limited | ICAO: BRT, Callsign: British, Name change to BA Connect Limited on 01 February 2006. Name changed from British Regional Airlines Limited. Formerly Manx Airlines (Europe) Ltd. | GB | AVCODES |
| 7 | TH | BA Connect Limited | ICAO: BRT, Callsign: British, Name change from British Airways CitiExpress Limited w.e.f. 01 February 2006. Merged into Flybe on 25 March 2007. | GB | AVCODES |
| 8 | TH | Raya Airways Sdn. Bhd. d/b/a Raya Airways | ICAO: RMY, Callsign: Raya Express, IATA Prefix: 539, Name changed from Transmile Air Services. | MAL | AVCODES |
| 9 | TH | Thomas, the Tank Engine and Friends | | TOY | TRAFFIC |
| 10 | TH&B | Toronto, Hamilton & Buffalo Ry. | 8/1920-7/1936 | | NAKINA |
| 11 | TH&B | TORONTO, HAMILTON & BUFFALO RWY. | | | PWRC |
| 12 | THA | Thai Airways International Public Company Ltd. | IATA: TG, Callsign: Thai, IATA Prefix: 217, | T | AVCODES |
| 13 | THA | Thai Airways International | IATA: TG | | ICAO1 |
| 14 | THA | Thalys | | F | TRAFFIC |
| 15 | THAA | THAI AIRWAYS INTERNATIONAL LTD | | | SCAC4 |
| 16 | THAB | TRANSPORTES HERNANDEZ | | | SCAC4 |
| 17 | THAD | TRANSPORT HALDARO INC | | | SCAC4 |
| 18 | THAE | THERMO BOND BUILDINGS INC | | | SCAC4 |
| 19 | THAG | TRANSPORTES HALCON | | | SCAC4 |
| 20 | THAH | THOMAS & HOWARD COMPANY OF HICKORY | | | SCAC3 |
| 21 | THAH | TRANSPORTES HERRERA | | | SCAC4 |
| 22 | THAI | THRASHER TRUCKING | | | SCAC3 |
| 23 | THAI | TRANSPORTES CHAIDES | | | SCAC4 |
| 24 | THAI | Royal Thai Army | | T | TRAFFIC |
| 25 | THAJ | THOMAS, A J & SONS INC | | | SCAC3 |
| 26 | THAK | THIEBAUD AND STEINACHER TRUCKING | | | SCAC3 |
| 27 | THAL | THORNE, AL TRANSPORT | | | SCAC3 |
| 28 | THAL | Thalys | | F | TRAFFIC |
| 29 | THAM | THAMES SALES YARD LTD | | | SCAC4 |
| 30 | THAM | Thamesway Buses | | GB | TRAFFIC |
| 31 | THAN | THREE AMIGOS SEAFOODS LTD | | | SCAC4 |
| 32 | THAP | THOMAS PETROLEUM | | | SCAC4 |
| 33 | THAR | THAMES RIVER MELONS LTD | | | SCAC4 |
| 34 | THAS | THRONE AUTO SERVICE, INC | | | SCAC3 |
| 35 | THAS | THASOS SHIPPING CO LTD | | | SCAC4 |
| 36 | THAT | THOMAS, AL, TRUCKING, INC | | | SCAC3 |
| 37 | THAT | THOMAS, AL TRUCKING INC | | | SCAC4 |
| 38 | THAU | CHONGQING TONGHUI GAS CO., LTD. | | PRC | BIC |
| 39 | THAU | TEKKOSHA HELLAS S.A.I. | | | SCAC3 |
| 40 | THAU | TEKKOSHA HELLAS S.A.I. | | | SCAC4 |
| 41 | THAV | T & H TRUCKING SERVICES INC | | | SCAC4 |
| 42 | THAW | THOMAS & WATSON TRUCKING | | | SCAC3 |
| 43 | THAW | THREE SSS GROUP LIMITED | | | SCAC4 |
| 44 | THAX | THARALDSON ETHANOL PLANT I LLC | | | SCAC4 |
| 45 | THAY | THAYERS WESTBORO & BOSTON EXPRESS, | | | SCAC3 |
| 46 | THAZ | THOMPSON HARDWOOD | | | PWRC |
| 47 | THB | Spark Air | | | ICAO1 |
| 48 | THB | Toronto, Hamilton & Buffalo Ry. Co. | 4/1938-1/1980; eliminated 10/1987 | | NAKINA |
| 49 | THB | CP Rail | 1/1994 | | NAKINA |
| 50 | THB | CP Rail System | eliminated 1/1997 | | NAKINA |
| 51 | THB | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 52 | THB | Toronto, Hamilton & Buffalo Ry. Co. | 4/38-1/80; eliminated 10/87 | | NRHS |
| 53 | THB | CP Rail | Jan-94 | | NRHS |
| 54 | THB | CP Rail System | eliminated 1/97 | | NRHS |
| 55 | THB | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | | NRHS |
| 56 | THB | CANADIAN PACIFIC RWY. CO. (CP RAIL0 [TORONTO, HAMILTON & BUFFALO RY] | | | PWRC |
| 57 | THB | Toronto, Hamilton and Buffalo Railway (Canadian Pacific Railway) | | | RSRV |
| 58 | THB | Toronto, Hamilton & Buffalo Railway Co. | | CDN | TRAFFIC |
| 59 | THB | Thurbo AG | | CH | VKM |
| 60 | THBE | THUNDERBALL EXPRESS | | | SCAC3 |
| 61 | THBE | TRANSPORTES HERMANOS BELTRAN S A DE | | | SCAC4 |
| 62 | THBH | THOMAS BROS TRUCKING INC | | | SCAC3 |
| 63 | THBI | THREE BROTHERS INC | | | SCAC3 |
| 64 | THBI | THREE B TRANSPORT INC | | | SCAC4 |
| 65 | THBJ | TH SERVICES INC | | | SCAC4 |
| 66 | THBK | THREE B TRUCKING INC (3-B TRUCKING | | | SCAC3 |
| 67 | THBK | TAR HEEL BROKERAGE LLC | | | SCAC4 |
| 68 | THBL | THOMPSON, BOB LANDSCAPING & TRUCKIN | | | SCAC3 |
| 69 | THBM | THOMPSON BUILDING MATERIALS INC | | | SCAC3 |
| 70 | THBM | TWO HARBOURS MARINE | | | SCAC4 |
| 71 | THBN | THEISEN BROTHERS INC | | | SCAC3 |
| 72 | THBN | THREE ZERO EIGHT NINE-ZERO NINE FOU | | | SCAC4 |
| 73 | THBO | THOMASTON TRANSPORTATION CO | | | SCAC3 |
| 74 | THBP | THUNDERBOLT EXPRESS INC | | | SCAC3 |
| 75 | THBR | THOMPSON BROS, INC | | | SCAC3 |
| 76 | THBR | THORNE HILL TRUCKING | | | SCAC4 |
| 77 | THBS | THREE B'S TRANSPORTATION COMPANY (3 | | | SCAC3 |
| 78 | THBT | THIBAULT, LUC TRANSPORT INC | | | SCAC4 |
| 79 | THBU | CONT-ASPHALT LTD. | | CH | BIC |
| 80 | THBU | CONT-ASPHAL LIMITED | | | SCAC4 |
| 81 | THBV | THOMPSON RIVER REDI MIX | | | SCAC4 |
| 82 | THBY | THOMPSON HARVEY BAY AREA LLC | | | SCAC4 |
| 83 | THC | Tar Heel Aviation, Inc. | Callsign: Tarheel, | USA | AVCODES |
| 84 | THC | Transportes Nacionales, C.A. | Callsign: Tranaven, | YV | AVCODES |
| 85 | THC | Tar Heel Aviation | | | ICAO1 |
| 86 | THCA | 3-C TRUCKING, S.A.R. Distribution, INC | | | SCAC3 |
| 87 | THCB | THREE ZERO THREE (303) CAB ASSOCIAT | | | SCAC3 |
| 88 | THCD | T H C INC | | | SCAC3 |
| 89 | THCF | THREE C INC (3 C INC) | | | SCAC3 |
| 90 | THCF | THERMAL PROCESS SYSTEMS INC | | | SCAC4 |
| 91 | THCG | THOMPSON CARTAGE INC | | | SCAC3 |
| 92 | THCH | THOMPSON, CRUSE H | | | SCAC3 |
| 93 | THCI | THICO INTERNATIONAL GROUP INC | | | SCAC3 |
| 94 | THCK | TRANSPORT HAROLD CARRUTHERS INC | | | SCAC4 |
| 95 | THCL | TOP HAT CHAYFFEURED LIMOUSINE SERVI | | | SCAC3 |
| 96 | THCM | TRILLIUM HEALTH CARE | | | SCAC4 |
| 97 | THCN | THOMPSON CONSTRUCTION CO | | | SCAC3 |
| 98 | THCO | THRIFT TRUCKING CO | | | SCAC3 |
| 99 | THCR | THREE COUNTRIES LLC | | | SCAC4 |
| 100 | THCT | THETA CABLE TELEVISION | | | SCAC3 |
