| 1 | TO | President Airlines | ICAO: PSD, IATA Prefix: 540, Desginator TO reinstated by IATA | K | AVCODES |
| 2 | TO | Alkan Air Ltd. | ICAO: AKN, Callsign: Alkan Air, Designator TO recalled by IATA | CDN | AVCODES |
| 3 | TO | Transavia France S.A.S. | ICAO: TVF, Callsign: France Soleil, Desginator TO reinstated by IATA | F | AVCODES |
| 4 | TO | The Medina Aviation Company | Callsign: Medina, | ET | AVCODES |
| 5 | TOA | Tropical Airlines Ltd. | Callsign: Tropical Airlines, | JA | AVCODES |
| 6 | TOA | Helicopter Services Ltd. | Callsign: Topcat, | GB | AVCODES |
| 7 | TOAA | TR TRUCKING INC | | | SCAC4 |
| 8 | TOAC | TRANSPORT AC ENTREGISTRE | | | SCAC4 |
| 9 | TOAE | TRANSPORTES OA | | | SCAC4 |
| 10 | TOAG | TRANSPORTES ARREOLA | | | SCAC4 |
| 11 | TOAH | TRANSPORTES OA | | | SCAC4 |
| 12 | TOAK | THREE (3) OF A KIND XPRESS INC | | | SCAC4 |
| 13 | TOAL | TORRES ALONSO, RAFAEL | | | SCAC4 |
| 14 | TOAO | TOMLINSONS SIGNS INC | | | SCAC4 |
| 15 | TOAP | TRANSPORTES ARRIAGA | | | SCAC4 |
| 16 | TOAQ | TRANSPORTES AQUA | | | SCAC4 |
| 17 | TOAR | TORRES TRUCKING | | | SCAC4 |
| 18 | TOAS | TONYS SONS MOVING & STORAGE | | | SCAC4 |
| 19 | TOAU | TOAGOSEI CO., LTD. | | J | BIC |
| 20 | TOAU | TOLYATTYAZOT LTD | | | SCAC4 |
| 21 | TOAV | TWO ONE TWO FIVE SIX SIX TWO (21256 | | | SCAC4 |
| 22 | TOAX | TTX COMPANY | | | SCAC4 |
| 23 | TOAY | TWO ONE THREE FOUR NINE SIX SEVEN ( | | | SCAC4 |
| 24 | TOB | Tobruk Air | Callsign: Tobruk Air, | LAR | AVCODES |
| 25 | TOB | Tobruk Air | IATA: 7T | | ICAO1 |
| 26 | TOBB | TOP LINE SUPPLIES INC | | | SCAC4 |
| 27 | TOBC | TOWNLINE PATTERNS | | | SCAC4 |
| 28 | TOBG | TNT TRANSPORTATION BROKERAGE LLC | | | SCAC4 |
| 29 | TOBI | TOBIN BROS MOVING & STORAGE | | | SCAC4 |
| 30 | TOBN | TRANSPORTES BINACIONALES R A | | | SCAC4 |
| 31 | TOBQ | TORRES, ROBERT INC | | | SCAC4 |
| 32 | TOBS | TORONTO ZOO | | | SCAC4 |
| 33 | TOBU | Tobu Railway | | J | TRAFFIC |
| 34 | TOBV | THREE OCEANS TRANSPORT INC | | | SCAC4 |
| 35 | TOBX | TTX COMPANY | | | SCAC4 |
| 36 | TOBY | TOBY'S TRUCKING, INC | | | SCAC1 |
| 37 | TOBY | TOWNLINE GROWERS INC | | | SCAC4 |
| 38 | TOC | Aerotropical, S.A. de C.V. | Callsign: Tropicmex, | MEX | AVCODES |
| 39 | TOC | Aerotropical | | | ICAO1 |
| 40 | TOC | New York Central System | 10/1966 | | NAKINA |
| 41 | TOC | Penn Central Transportation Co. | 4/1970-1/1975 | | NAKINA |
| 42 | TOC | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/1976 | | NAKINA |
| 43 | TOC | Consolidated Rail Corp. | added 4/1976; 1/1980; eliminated 1/1983; added 5/1983; eliminated 7/1999; 1/1994 | | NAKINA |
| 44 | TOC | New York Central System | Oct-66 | | NRHS |
| 45 | TOC | Penn Central Transportation Co. | 4/70-1/75 | | NRHS |
| 46 | TOC | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | | NRHS |
| 47 | TOC | Consolidated Rail Corp. | added 4/76; 1/80; eliminated 1/83; added 5/83; eliminated 7/99; 1/94 | | NRHS |
| 48 | TOC | CONSOLIDATED RAIL CORP. [PENN CENTRAL; NEW YORK CENTRAL; TOLEDO & OHIO CENTRAL RY] | | | PWRC |
| 49 | TOC | Toledo & Ohio Central Railway (Conrail) | | | RSRV |
| 50 | TOC | Toledo and Ohio Central Railway | | USA | TRAFFIC |
| 51 | TOCA | TRANS OCEAN CARRIER INC | | | SCAC4 |
| 52 | TOCB | TRANSPORTES CARBA SA DE CV | | | SCAC4 |
| 53 | TOCC | TONAWANDA COKE CORP. | | | PWRC |
| 54 | TOCC | TRANSOCEANIC CABLE SHIP COMPANY LLC | | | SCAC4 |
| 55 | TOCD | TURNER OIL CO INC | | | SCAC4 |
| 56 | TOCE | TOTAL OCEAN | | | SCAC1 |
| 57 | TOCE | TOTAL OCEAN MARINE SERVICES INC | | | SCAC4 |
| 58 | TOCG | TRANSPORTES DE CARGA GUTIERREZ | | | SCAC4 |
| 59 | TOCH | TOWLE, CHARLES C | | | SCAC1 |
| 60 | TOCHIO | Tochio Railway | | J | TRAFFIC |
| 61 | TOCN | TWO SIX FOUR SIX-FIVE EIGHT FOUR NI | | | SCAC4 |
| 62 | TOCP | TYLER OIL CO | | | SCAC4 |
| 63 | TOCQ | TORRES CONTAINER CONNECTION | | | SCAC4 |
| 64 | TOCS | TII LOGISTICS INC | | | SCAC4 |
| 65 | TOCT | TOTEM OCEAN TRAILER EXPRESS INC | | | SCAC4 |
| 66 | TOCV | THIEL OIL CO | | | SCAC4 |
| 67 | TOCX | True's Oil Co. | 7/1935-1/1943; 1/1945 (not listed); 1/1946-10/1957; eliminated 7/1958 | | NAKINA |
| 68 | TOCX | True's Oil Co. | 4/38-10/57; eliminated 7/58 | | NRHS |
| 69 | TOCX | TRUE'S OIL CO. | | | PWRC |
| 70 | TOCX | TTX COMPANY | | | SCAC4 |
| 71 | TOCZ | TOCCA CASKET CO. | | | PWRC |
| 72 | TODA | TOP OF TEXAS LOGISTICS INC | | | SCAC4 |
| 73 | TODB | TOTAL DISTRIBUTION INC | | | SCAC4 |
| 74 | TODC | TOTAL LOGISTICAL CONCEPTS LLC | | | SCAC4 |
| 75 | TODD | TODD CHARTER SERVICE INC | | | SCAC4 |
| 76 | TODF | TJM & CO | | | SCAC4 |
| 77 | TODJ | TASSO EXPRESS LLC | | | SCAC4 |
| 78 | TODL | TTS LLC | | | SCAC4 |
| 79 | TODN | TODAY CARTAGE, INC | | | SCAC1 |
| 80 | TODQ | TRANSPORT STEPHANE HUET INC | | | SCAC4 |
| 81 | TODS | TODD-ELSTON OIL | | | SCAC4 |
| 82 | TODU | TTS LLC | | | RSRV |
| 83 | TODV | TRANSPORTES DEL COBRE | | | SCAC4 |
| 84 | TODW | TRANSOCEAN DEEPWATER DRILLING INC | | | SCAC4 |
| 85 | TODX | The David J. Joseph Co. | added 10/2008 | | NAKINA |
| 86 | TODX | THE DAVID J. JOSEPH CO. | | | PWRC |
| 87 | TODX | THE DAVID J JOSEPH COMPANY | | | SCAC4 |
| 88 | TODY | TODCO | | | SCAC4 |
| 89 | TOE | Texas, Oklahoma & Eastern R.R. Co. | 1/1975-7/2005 | | NAKINA |
| 90 | TOE | Texas, Oklahoma & Eastern R.R. Co. | 1/75-7/2000 | | NRHS |
| 91 | TOE | TEXAS, OKLAHOMA & EASTERN RAILROAD | | | PWRC |
| 92 | TOE | Texas, Oklahoma and Eastern Railroad | | | RSRV |
| 93 | TOE | Texas, Oklahoma and Eastern Railroad | | USA | TRAFFIC |
| 94 | TOEA | TRANSPORTES EXTRA | | | SCAC4 |
| 95 | TOEB | TST LOGISTICS INC | | | SCAC4 |
| 96 | TOEC | TRANSPORTES ORION ESPECIALIZADOS SA | | | SCAC4 |
| 97 | TOEI | Toei Subway | | J | TRAFFIC |
| 98 | TOEJ | TRANS ORIENT EXPRESS INC | | | SCAC4 |
| 99 | TOELN | Tölner GmbH | | DE | VKM |
| 100 | TOEO | TWO ONE EIGHT SEVEN SIX ZERO ONE (2 | | | SCAC4 |
