| 1 | BRT | British Regional Airlines Limited | IATA: TH, 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 |
| 2 | BRT | British Regional Airlines Limited | IATA: JE, ICAO designator changed from MXE / IATA designator changed to TH | GB | AVCODES |
| 3 | BRT | British Airways CitiExpress Limited | IATA: TH, 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 |
| 4 | BRT | BA Connect Limited | IATA: TH, Callsign: British, Name change from British Airways CitiExpress Limited w.e.f. 01 February 2006. Merged into Flybe on 25 March 2007. | GB | AVCODES |
| 5 | BRT | London Helicopter Centres Ltd | Callsign: British, Name changed to BIH (Onshore) Ltd. | GB | AVCODES |
| 6 | BRT | BIH (Onshore) Ltd | Callsign: British, Name changed to British International Helicopter Services Limited. Name changed from London Helicopter Centres Ltd. | GB | AVCODES |
| 7 | BRT | British International Helicopter Services Limited | Callsign: British, Name changed from BIH (Onshore) Ltd. w.e.f. 12 january 2018. Name changed from London Helicopter Centres Ltd. w.e.f. 29 April 2014. | GB | AVCODES |
| 8 | BRT | British Regional Airlines | | | ICAO1 |
| 9 | BRTA | BERTA BROS TRANSPORTATION | | | SCAC3 |
| 10 | BRTA | BROTHERS TRUCK LINE | | | SCAC4 |
| 11 | BRTB | BRITT TRUCKING COMPANY | | | SCAC3 |
| 12 | BRTC | BLUE ROCK TRANSPORTATION CO. | | | PWRC |
| 13 | BRTC | BROWN TRANSFER COMPANY | | | SCAC3 |
| 14 | BRTC | BROWN TRANSFER COMPANY | | | SCAC4 |
| 15 | BRTD | BRITTON MOTOR SERVICE INC | | | SCAC3 |
| 16 | BRTE | BARRETTE, SYLVAIN INC | | | SCAC4 |
| 17 | BRTF | BROWNS TRANSFER | | | SCAC3 |
| 18 | BRTG | BARRETT, G | | | SCAC3 |
| 19 | BRTG | Brenntag CEE GmbH | | AT | VKM |
| 20 | BRTH | BARTHOLOMEW, JOHN B | | | SCAC3 |
| 21 | BRTH | BARTHOLOMEW, JOHN B | | | SCAC4 |
| 22 | BRTI | B R TRUCKING CO INC | | | SCAC3 |
| 23 | BRTI | B R TRUCKING CO INC OF NORTH BERGEN | | | SCAC4 |
| 24 | BRTJ | BARR TRANSPORTATION CORP | | | SCAC3 |
| 25 | BRTK | B & R TUBGRINDING LIMITED | | | SCAC4 |
| 26 | BRTL | BROOKS TRUCK LINE | | | SCAC3 |
| 27 | BRTM | BERT TRANSMISSION | | | SCAC4 |
| 28 | BRTN | BARTON TRUCK LINES INC | | | PWRC |
| 29 | BRTO | BRYANTON TRANSPORT | | | SCAC4 |
| 30 | BRTP | BRANTLEY TRUCKING, INC | | | SCAC3 |
| 31 | BRTQ | BARTON, ROBERT | | | SCAC3 |
| 32 | BRTQ | BURTT, ALLISON B | | | SCAC4 |
| 33 | BRTR | BLUE ROCK TRANSPORTATION CO. | | | PWRC |
| 34 | BRTR | BLUE RIDGE TRANSFER COMPANY INCORPO | | | SCAC3 |
| 35 | BRTR | BROWN, RON TRANSPORT | | | SCAC4 |
| 36 | BRTRP | British Transport Police | | GB | TRAFFIC |
| 37 | BRTS | BREITEN TRUCKING | | | SCAC3 |
| 38 | BRTT | BRIGHT TRANSPORTATION, INC. | | | SCAC3 |
| 39 | BRTT | BRIGHT TRANSPORTATION LP | | | SCAC4 |
| 40 | BRTU | HALCYON TANKERS 2022 LTD | | GB | BIC |
| 41 | BRTU | BRITISH TRAFFIC & ELECTRIC CO. | | | SCAC3 |
| 42 | BRTU | GROUPE SAMAT UK LTD | | | SCAC4 |
| 43 | BRTV | BRANDT TRANSPORT SERVICES, LLC | | | SCAC4 |
| 44 | BRTW | BRIARTOWN EXPRESS CORP | | | SCAC4 |
| 45 | BRTX | BELLMAN RIVER TERMINAL, INC. | | | PWRC |
| 46 | BRTX | BRANDT ROAD RAIL CORPORATION | | | SCAC4 |
