| 1 | TR | Transbrasil S.A. Linhas Aereas | ICAO: TBA, Callsign: Transbrasil, IATA Prefix: 653, Suspended Operations on 03 December 2001. ICAO callsign changed from Tango Romeo | BR | AVCODES |
| 2 | TR | Compania de Aviacion Trans-Europa | Callsign: Trans Europa, | E | AVCODES |
| 3 | TR | Tiger Airways Singapore Pte Ltd t/a Tigerair | ICAO: TGW, Callsign: Stripe, IATA Prefix: 388, Name change to Scoot Tigerair Pte. Ltd. (Merged with Scoot.) | SGP | AVCODES |
| 4 | TR | Transbrasil S.A. Linhas Aereas | ICAO: TBA, Callsign: Tango Romeo, Suspended Operations on 03 December 2001. ICAO callsign changed to Transbrasil | BR | AVCODES |
| 5 | TR | Scoot Tigerair Pte. Ltd. | ICAO: TGW, Callsign: Stripe, IATA Prefix: 668, Name changed to Scoot Tigerair Pte. Ltd. d/b/a Scoot. Name changed from Scoot Tigerair Pte. Ltd. d/b/a Scoot. ICAO Callsign changed to Scooter. Name change from Tiger Airways Singapore Pte Ltd t/a Tigerair. | SGP | AVCODES |
| 6 | TR | Scoot Tigerair Pte. Ltd. d/b/a Scoot | ICAO: TGW, Callsign: Scooter, IATA Prefix: 668, Name changed to Scoot Pte. Ltd. d/b/a Scoot. Name changed from Scoot Tigerair Pte. Ltd. d/b/a Scoot. ICAO callsign changed from Stripe. Name change from Tiger Airways Singapore Pte Ltd t/a Tigerair. | SGP | AVCODES |
| 7 | TR | Scoot Pte. Ltd. d/b/a Scoot | ICAO: TGW, Callsign: Scooter, IATA Prefix: 668, Name changed from Scoot Tigerair Pte. Ltd. d/b/a Scoot. ICAO callsign changed from Stripe. Name change from Tiger Airways Singapore Pte Ltd t/a Tigerair. | SGP | AVCODES |
| 8 | TR | Tomahawk Ry., Ltd. Partnership | added 4/1992; eliminated 7/1993; 1/1994 (not listed); eliminated 10/1997; 7/2000 (not listed); added 10/2000; 7/2005 | | NAKINA |
| 9 | TR | Tomahawk Ry., Ltd. Partnership | added 4/92; eliminated 7/93; 1/94; eliminated 10/97; 7/2000; added 10/2000 | | NRHS |
| 10 | TR | TOMAHAWK RAILWAY, LP | | | PWRC |
| 11 | TR | Tomahawk Railway | | | RSRV |
| 12 | TR | TOMAHAWK RAILWAY L P | | | SCAC4 |
| 13 | TR | National Rail Corporation - TrailerRail | | AUS | TRAFFIC |
| 14 | TR | TR Trans Rail GmbH | | CH | VKM |
| 15 | TRA | Transavia | IATA: HV, Callsign: Transavia, IATA Prefix: 979, | NL | AVCODES |
| 16 | TRA | Basiq Air | IATA: HV, Merged back into Transavia. Low cost subsidary of Transavia | NL | AVCODES |
| 17 | TRA | Trans Air, Inc. | Callsign: Trans Cab, | USA | AVCODES |
| 18 | TRA | Transavia Holland B.V. | IATA: HV, Callsign: Transavia, | NL | AVCODES |
| 19 | TRA | Transavia Holland | IATA: HV | | ICAO1 |
| 20 | TRA | TENNESSEE RAILROAD CO. | | | PWRC |
| 21 | TRA | | | RC | TRAFFIC |
| 22 | TRAA | TRANSPORTES AMERICANOS S A DE C V | | | SCAC4 |
| 23 | TRABANT | Trabant | | D | TRAFFIC |
| 24 | TRAC | ONE TO THREE (1 TO 3) TRADE CO LLC | | | SCAC4 |
| 25 | TRACC | Traccion Rail s.l. | Part of the AZVI Group | E | TRAFFIC |
| 26 | TRACC | Traccion Rail s.l. | | ES | VKM |
| 27 | TRACK | ON-TRACK, s.r.o. | | CZ | VKM |
| 28 | TRACKLESS | Trackless Transit | | US-NJ | TRAFFIC |
| 29 | TRAD | TRADE CARRIER | | | SCAC1 |
| 30 | TRAD | TRIAD TRANSPORTATION INC | | | SCAC4 |
| 31 | TRADB | Traditionsbus Berlin | | D | TRAFFIC |
| 32 | TRAF | TRANSPORTES REALIZA S A | | | SCAC4 |
| 33 | TRAG | TRADING POST | | | SCAC4 |
| 34 | TRAH | TRANSPORTES AGUIRRE | | | SCAC4 |
| 35 | TRAI | TRIPLE A TRANSPORT INC | | | SCAC4 |
| 36 | TRAIL | Transrail Freight | | GB | TRAFFIC |
| 37 | TRAIN | Train Rental International | | EU | TRAFFIC |
| 38 | TRAK | Trakcia AD / Тракция АД | | BG | VKM |
| 39 | TRAKC | TRAKCE A.S. Spółka Akcyjna Oddzial w Polsce | | PL | VKM |
| 40 | TRAL | TRANSYSTEMS LLC | | | SCAC4 |
| 41 | TRAM | American Refrigerator Transit Co. | added 10/1961; eliminated 7/1962 | | NAKINA |
| 42 | TRAM | AMERICAN REFRIGERATOR TRANSIT CO. | | | PWRC |
| 43 | TRAM | TRANSMAXX | | | SCAC4 |
| 44 | TRAME | TRAMESA S.A | | ES | VKM |
| 45 | TRAMO | TRAMO RAIL, a.s. | | CZ | VKM |
| 46 | TRAN | TRANSCON LINES | | | PWRC |
| 47 | TRAN | TRANSOCEAN MARITIME AGENCIES SA | | | SCAC4 |
| 48 | TRANS | TRANSPORTSERVIS, spol. s r.o. | | CZ | VKM |
| 49 | TRANSCO | TransCo | | FAN | TRAFFIC |
| 50 | TRANSGOR | Transgór Spółka Akcyjna – przedsiębiorstwo transportowe z Mysłowic | | PL | TRAFFIC |
| 51 | TRANSKOM | Transkom s.j. | City: Piekary Śląskie | PL | TRAFFIC |
| 52 | TRANSLUB | Przedsiębiorstwo Transportowe Translub sp. z o.o. | | PL | TRAFFIC |
| 53 | TRANSLUD | TRANSLUD Przewozy Autokarowe Jan Domosławski | | PL | TRAFFIC |
| 54 | TRANSMAC | Transportes Urbanos de Macau | | | TRAFFIC |
| 55 | TRANSN | Transports Publics Neuchâtelois | | CH | TRAFFIC |
| 56 | TRAP | TRANSPORT SERVICE CO | | | SCAC4 |
| 57 | TRAPL | Trakcja S.A. | | PL | VKM |
| 58 | TRAQ | TRANSPORTERS | | | SCAC4 |
| 59 | TRAR | TRANSPORTES REFRIGERADOS ARAMBURO S | | | SCAC4 |
| 60 | TRAS | TRANSCO SHIPPING (USA) INC | | | SCAC4 |
| 61 | TRAS | Trasfeimer Trasporti Ferroviari Innovativi Meridionali S.p.A. | | IT | VKM |
| 62 | TRASK | TRATEC SK s.r.o | Real: TRA | SK | TRAFFIC |
| 63 | TRAU | ASSOCIATED TRANSPORT LINE | | | PWRC |
| 64 | TRAU | Associated Transport Line | | | RSRV |
| 65 | TRAU | ASSOCIATED TRANSPORT LINE | | | SCAC4 |
| 66 | TRAV | TRANSPORTES VIRAMONTES | | | SCAC4 |
| 67 | TRAV | Transavia | | | TRAFFIC |
| 68 | TRAX | Terminal Refining Co. (Keystone Oil & Manufacturing Co.) | 8/1920 | | NAKINA |
| 69 | TRAX | American Refrigerator Transit Co. | added 4/1954; 10/1957-4/1970; eliminated 7/1970 | | NAKINA |
| 70 | TRAX | Railtex Corp. | added 7/1978 | | NAKINA |
| 71 | TRAX | Railtex Inc. | 1/1980 | | NAKINA |
| 72 | TRAX | Railtex Corp. | 1/1994 | | NAKINA |
| 73 | TRAX | Railtex Inc. | 7/2000-7/2005 | | NAKINA |
| 74 | TRAX | American Refrigerator Transit Co. | added 4/54; 10/57-4/70; eliminated 7/70 | | NRHS |
| 75 | TRAX | Railtex Corp. | added 7/78 | | NRHS |
| 76 | TRAX | Railtex Inc. | Jan-80 | | NRHS |
| 77 | TRAX | Railtex Corp. | Jan-94 | | NRHS |
| 78 | TRAX | Railtex Inc. | Jul-00 | | NRHS |
| 79 | TRAX | *KEYSTONE OIL & MANUFACTURING CO. [TERMINAL REFINING CO.] | | | PWRC |
| 80 | TRAX | +RAILTEX, INC. [AMERICAN REFRIGERATOR TRANSIT CO.] | | | PWRC |
| 81 | TRAX | Railtex | | | RSRV |
| 82 | TRAX | RAILTEX, INC. | | | SCAC4 |
| 83 | TRAY | TRANSPORTADORA DE COSS S A DE C V | | | SCAC4 |
| 84 | TRB | Ukraine Transavia | Callsign: Kirovtrans, Ceased operations | UA | AVCODES |
| 85 | TRB | Thai Regional Aviation Company Limited d/b/a Thai Regional | IATA: RW, Designator RW recalled by IATA. | T | AVCODES |
| 86 | TRB | Thai Regional Aviation Company Limited d/b/a Thai Regional | Name changed to Rabbit Wings Airways Company Limited. Designator RW recalled by IATA. | T | AVCODES |
| 87 | TRB | Rabbit Wings Airways Company Limited | Name changed from Thai Regional Aviation Company Limited d/b/a Thai Regional. Designator RW recalled by IATA. | T | AVCODES |
| 88 | TRB | Ukraine Transavia | | | ICAO1 |
| 89 | TRBA | TRANSPORT BLANEY INC | | | SCAC4 |
| 90 | TRBB | TRB TWO THOUSAND (2000) INC | | | SCAC4 |
| 91 | TRBD | TRANSPORTES BANDA REFRIGERADOS | | | SCAC4 |
| 92 | TRBG | TRICE TRUCKING INC | | | SCAC4 |
| 93 | TRBH | TRIER TRANSPORT | | | SCAC4 |
| 94 | TRBI | TRANSPORT RABEL INC | | | SCAC4 |
| 95 | TRBJ | TRANSORT REGINALD JACQUES | | | SCAC4 |
| 96 | TRBK | T.R.N. TRANSPORTATION, INC | | | SCAC1 |
| 97 | TRBK | T R N TRANSPORTATION INC | | | SCAC4 |
| 98 | TRBM | TRANSPORT ROBERT PRIMEAU INC | | | SCAC4 |
| 99 | TRBP | TRANSPORTES ROCO | | | SCAC4 |
| 100 | TRBR | TRAILER BRIDGE INC (TRUCK) | | | SCAC1 |
