| 7901 | TPTX | Trailer Train Co. | added 10/80; eliminated 4/81 | | NRHS |
| 7902 | TPTX | Trailer Train Co. | 1/94-7/2000 | | NRHS |
| 7903 | TPTX | TRAILER TRAIN CO. | | | PWRC |
| 7904 | TPTX | Trailer Train (TTX Corporation) | | | RSRV |
| 7905 | TPTY | T & P TRUCKING LTD | | | SCAC4 |
| 7906 | TPTZ | THREE (3) PLUS TRANSPORTATION | | | SCAC4 |
| 7907 | TPU | Trans American Airlines, S.A. TACA Peru | IATA: T0, Callsign: Trans Peru, IATA Prefix: 530, Name changed to Avianca Peru. Established in 1999. Commenced operations in July 1999. | PE | AVCODES |
| 7908 | TPU | Trans American Airlines, S.A. Avianca Peru | IATA: T0, Callsign: Trans Peru, IATA Prefix: 530, Ceased operations on 10 May 2020. Name changed from Trans American Airlines, S.A. TACA Peru. Established in 1999. Commenced operations in July 1999. | PE | AVCODES |
| 7909 | TPU | Trans American Airlines (Trans Am) | | | ICAO1 |
| 7910 | TPUA | TRIPLE M AUTO PARTS | | | SCAC4 |
| 7911 | TPUE | TRIPLE E LLC | | | SCAC4 |
| 7912 | TPUI | TRANSPORT PRODUCTS UNLIMITED INC | | | SCAC4 |
| 7913 | TPUM | TRANSPORTES UNIMEX SA DE CV | | | SCAC4 |
| 7914 | TPUQ | TELLURIC PETROLEUM TRANSPORT INC | | | SCAC4 |
| 7915 | TPUR | TRANSPORT PURAN | | | SCAC4 |
| 7916 | TPUS | TRIPLUS INC | | | SCAC4 |
| 7917 | TPUT | THIRD PRODUCTS TANKERS, INC. | | | SCAC4 |
| 7918 | TPV | Thai Pacific Airlines Business Company Ltd. | IATA: 3P, Callsign: Thai Pacific, | T | AVCODES |
| 7919 | TPV | Temple Aviacion S.L. | | E | AVCODES |
| 7920 | TPV | Thai Pacific Airlines Business | | | ICAO1 |
| 7921 | TPVA | TRANSPORTES V ANDA | | | SCAC4 |
| 7922 | TPVC | TRANS ATLANTIC PRODUCT & SHIPPING S | | | SCAC4 |
| 7923 | TPVI | TRANSPORTATION SERVICES, INC | | | SCAC1 |
| 7924 | TPVK | TRANSPORTES REFRIGERADOS PANDAS TRU | | | SCAC4 |
| 7925 | TPVM | TRANS-PLUS V M INC | | | SCAC4 |
| 7926 | TPVN | TRANSPORT ON-TIME | | | SCAC4 |
| 7927 | TPVO | TRANS PRO OVERNITE CO | | | SCAC4 |
| 7928 | TPVQ | TRANSPORTES VAZQUEZ | | | SCAC4 |
| 7929 | TPVR | TRANSPORTES VAR | | | SCAC4 |
| 7930 | TPVU | TIN PRODUCTS INC | | | SCAC4 |
| 7931 | TPVW | TRIPLE R DRIVER SERVICE | | | SCAC4 |
| 7932 | TPVY | TREALSHIP SERVICES INC | | | SCAC4 |
| 7933 | TPW | Toledo, Peoria & Western Ry. Co. | 1/1975-1/1980; eliminated 1/1984 | | NAKINA |
| 7934 | TPW | The Atchison, Topeka and Santa Fe Ry. Co. | eliminated 7/1988 | | NAKINA |
| 7935 | TPW | Toledo, Peoria & Western Ry. Co. | added 7/1989; eliminated 4/1991 | | NAKINA |
| 7936 | TPW | Toledo, Peoria & Western Ry. Corp. | added 4/1991; eliminated 10/1992; 1/1994; added 4/1995; 7/2000; eliminated 7/2004; 7/2005 | | NAKINA |
| 7937 | TPW | Toledo, Peoria & Western Ry. Co. | 1/75-1/80 | | NRHS |
| 7938 | TPW | The Atchison, Topeka and Santa Fe Ry. Co. | eliminated 7/88 | | NRHS |
| 7939 | TPW | Toledo, Peoria & Western Ry. Co. | added 7/89; eliminated 4/91 | | NRHS |
| 7940 | TPW | Toledo, Peoria & Western Ry. Corp. | added 4/91; eliminated 10/92; 1/94; added 4/95; 7/2000 | | NRHS |
| 7941 | TPW | BNSF RWY. [BURLINGTON NORTHERN & SANTA FE; ATSF; TOLEDO, PEORIA & WESTERN RWY] | | | PWRC |
| 7942 | TPW | Toledo, Peoria and Western Railroad (BNSF Railway) | | | RSRV |
| 7943 | TPW | TOLEDO PEORIA & WESTERN RAILWAY COR | | | SCAC4 |
| 7944 | TPW | Toledo, Peoria & Western Railroad | | USA | TRAFFIC |
| 7945 | TPWC | TROPICAL OIL LLC | | | SCAC4 |
| 7946 | TPWG | TTL TROPICAL TRAILER LEASING | | | SCAC4 |
| 7947 | TPWI | TROPHY WHITETAIL REPRODUCTIONS | | | SCAC4 |
| 7948 | TPWM | THOMPSON PUMP MIDWEST | | | SCAC4 |
| 7949 | TPWS | THREE P (3P) SOLUTIONS LLC | | | SCAC4 |
| 7950 | TPWT | TERRYS CONCRETE PUMPING | | | SCAC4 |
| 7951 | TPWX | TEXAS PARKS & WILDLIFE DEPT. | | | PWRC |
| 7952 | TPWZ | (TPW) TOLEDO, PEORIA & WESTERN RAILWAY CORPORATION | | | PWRC |
| 7953 | TPWZ | TOLEDO PEORIA & WESTERN RAILWAY COR | | | SCAC4 |
| 7954 | TPX | Transportes Aereos de Xalapa, S.A. de C.V. | Callsign: Transxalpa, | MEX | AVCODES |
| 7955 | TPX | Transportes Aereos De Xalapa | | | ICAO1 |
| 7956 | TPX | Trojan Powder Co. | 8/1920-7/1935 | | NAKINA |
| 7957 | TPX | Trojan Powder Co., care of Pennsylvania Trojan Powder Co. | 7/1937-10/1957 | | NAKINA |
| 7958 | TPX | Trojan Powder Co. | eliminated 7/1958 | | NAKINA |
| 7959 | TPX | Trojan Powder Co. | 4/38-1/52 | | NRHS |
| 7960 | TPX | Trojan Powder Co., care of Pennsylvania Trojan Powder Co. | Oct-57 | | NRHS |
| 7961 | TPX | Trojan Powder Co. | eliminated 7/58 | | NRHS |
| 7962 | TPX | TROJAN POWDER CO. | | | PWRC |
| 7963 | TPX | TransPng other | | | TRAFFIC |
| 7964 | TPX | Trans-Pennine Express | | UK | VKM |
| 7965 | TPXA | TRANSPORTES MARTINEZ | | | SCAC4 |
| 7966 | TPXB | TRANSPORTATION PARTNERS | | | SCAC4 |
| 7967 | TPXE | TRANSPORTES COPADO | | | SCAC4 |
| 7968 | TPXF | TRAPEX | | | SCAC4 |
| 7969 | TPXG | TLC TRANSPORTATION | | | SCAC4 |
| 7970 | TPXH | TRANSPORTES PIMENTEL | | | SCAC4 |
| 7971 | TPXI | TIPTOP EXPRESS INC | | | SCAC4 |
| 7972 | TPXK | T P EXPRESS INC | | | SCAC4 |
| 7973 | TPXN | TRIPLE A EXPRESS INC | | | SCAC4 |
| 7974 | TPXO | TRANSPORTES SOL | | | SCAC4 |
| 7975 | TPXQ | TRANSPORTATION PLUS | | | SCAC4 |
| 7976 | TPXS | TOPAC ENTERPRISES INC | | | SCAC4 |
| 7977 | TPXU | (TPHU) TIPHOOK CONTAINER RENTAL COMPANY LTD. | | | PWRC |
| 7978 | TPXU | Tiphook Container Rental Limited | | | RSRV |
| 7979 | TPXU | TRANSAMERICA LEASING INC | | | SCAC4 |
| 7980 | TPXV | TRANSPORT EXECUTIVES INC | | | SCAC4 |
| 7981 | TPXY | TRICAP INTERNATIONAL LLC | | | SCAC4 |
| 7982 | TPY | Trans-Provincial Airlines Ltd. | Callsign: Trans Provincial, | CDN | AVCODES |
| 7983 | TPY | Trans-Provincial Airlines Ltd. | IATA: CD, Callsign: Trans Provincial, Designator CD recalled by IATA | CDN | AVCODES |
| 7984 | TPY | Trans-Provincial Airlines | | | ICAO1 |
| 7985 | TPYA | TRANSPORTES YANEZ | | | SCAC4 |
| 7986 | TPYC | TRIPLE L LOGISTICS LLC | | | SCAC4 |
| 7987 | TPYE | TRANSPORTES REYES | | | SCAC4 |
| 7988 | TPYI | TRANSPORT AYB INC | | | SCAC4 |
| 7989 | TPYK | TOMBERLIN, PAUL TRUCKING LLC | | | SCAC4 |
| 7990 | TPYM | TRANSPORTES OLYMPIC | | | SCAC4 |
| 7991 | TPYR | TRIPLE C CARRIER LLC | | | SCAC4 |
| 7992 | TPYS | THIRD PARTY SERVICES | | | SCAC1 |
| 7993 | TPYS | THIRD PARTY SERVICES INC | | | SCAC4 |
| 7994 | TPYT | TRACTOPARTES TRANSPORTS COLAZO | | | SCAC4 |
| 7995 | TPYY | TRANSPORTES YEYOS | | | SCAC4 |
| 7996 | TPZ | Transportes La Paz, S.A. de C.V. | Callsign: Transpaz, | MEX | AVCODES |
| 7997 | TPZ | Transportes La Paz | | | ICAO1 |
| 7998 | TPZ | UP [MISSOURI PACIFIC RAILROAD] | | | PWRC |
| 7999 | TPZ | Missouri Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 8000 | TPZ | UNION PACIFIC RAILROAD COMPANY | | | SCAC4 |
