| 1 | BY | Britannia Airways Limited | ICAO: BAL, Callsign: Britannia, IATA Prefix: 754, Name changed to Thomsonfly Limited | GB | AVCODES |
| 2 | BY | Britannia Airways Ltd. t/a Budget Air | ICAO: BAL, Callsign: Thomson, IATA Prefix: 754, | GB | AVCODES |
| 3 | BY | Thomsonfly Limited | ICAO: TOM, Callsign: Tomson, IATA Prefix: 754, Name changed to Thomson Airways Limited w.e.f. 27 October 2008. Name changed from Britannia Airways Limited w.e.f. 01 November 2005 | GB | AVCODES |
| 4 | BY | TUI Airways Limited | ICAO: TOM, Callsign: TUI Air, IATA Prefix: 754, Name changed from Thomson Airways Limited w.e.f. 02 October 2017. ICAO Callsign changed from Tomson. ICAO callsign changed to Tomjet. | GB | AVCODES |
| 5 | BY | Thomson Airways Limited | ICAO: TOM, Callsign: Tomson, IATA Prefix: 754, Name changed to TUI Airways Limited w.e.f. 02 October 2017. Name changed from Thomsonfly Limited w.e.f. 27 October 2008. | GB | AVCODES |
| 6 | BY | TUI Airways Limited | ICAO: TOM, Callsign: Tomjet, IATA Prefix: 754, Name changed from Thomson Airways Limited w.e.f. 02 October 2017. ICAO Callsign changed from Tomson. ICAO callsign changed from TUI Air. | GB | AVCODES |
| 7 | BYA | Berry Aviation, Inc. | Callsign: Berry, | USA | AVCODES |
| 8 | BYA | Berry Aviation | | | ICAO1 |
| 9 | BYAA | BYERS, DAVID | | | SCAC4 |
| 10 | BYAB | BUYA TRANSPORTATION | | | SCAC4 |
| 11 | BYAC | BAY AREA RECYCLING CENTER | | | SCAC3 |
| 12 | BYAC | BARRY, ELWOOD | | | SCAC4 |
| 13 | BYAD | BAY AREA RIGGING & DRAYING INC | | | SCAC3 |
| 14 | BYAF | BAY AREA FORWARDERS INC | | | SCAC3 |
| 15 | BYAF | BAY AREA PORT SERVICES LLC | | | SCAC4 |
| 16 | BYAF | Belarusian Air Force | Air Force and Air Defence Forces of the Republic of Belarus: Ваенна-паветраныя сілы і войскі супрацьпаветранай абароны Рэспублікі Беларусь | BY | TRAFFIC |
| 17 | BYAG | BAY AREA GARMENT SERVICE | | | SCAC3 |
| 18 | BYAI | BAILEY, A R INC | | | SCAC3 |
| 19 | BYAK | BOYS, A TRUCKING | | | SCAC4 |
| 20 | BYAL | BAY AREA OIL CO | | | SCAC4 |
| 21 | BYAM | BAY AREA MOVERS | | | SCAC3 |
| 22 | BYAM | BAY AREA MOVERS INC | | | SCAC4 |
| 23 | BYAN | BRYANT MOVING & STORAGE | | | SCAC3 |
| 24 | BYAO | BAY AREA CONTRACT TRANSPORTATION SE | | | SCAC3 |
| 25 | BYAO | BOYLES, A T LTD | | | SCAC4 |
| 26 | BYAP | BAY AREA TRANSPORT INC | | | SCAC3 |
| 27 | BYAQ | BRYANT TRANSPORTS INC | | | SCAC3 |
| 28 | BYAR | BYARS OIL COMPANY INC | | | SCAC3 |
| 29 | BYAT | BAY AIR TRANSPORTATION INC | | | SCAC3 |
| 30 | BYAW | BYARS, W DENNIS | | | SCAC3 |
| 31 | BYAW | BABY RED TRUCKING | | | SCAC4 |
| 32 | BYAX | Byerlyte Corp. | 1/1945-1/1952; eliminated 10/1953 | | NAKINA |
| 33 | BYAX | Byerlyte Corp. | 1/52; eliminated 10/53 | | NRHS |
| 34 | BYAX | BYERLYTE CORP. | | | PWRC |
| 35 | BYB | Bayern Bahn Betriebsgesellschaft | This company is the "commercial" part of the Bayerisches Eisenbahnmuseum in Nördlingen. They operate freight services to Wassertrüdingen and work trains to Dinkelsbühl, Dombühl and Gunzenhausen. | D | TRAFFIC |
| 36 | BYB | Bayern-Bahn-Betriebsgesellschaft | | DE | VKM |
| 37 | BYBB | BYBEE, BILLY TRUCKING | | | SCAC3 |
| 38 | BYBB | BYBEE, BILLY TRUCKING | | | SCAC4 |
| 39 | BYBC | BYRD BROTHERS LLC | | | SCAC4 |
| 40 | BYBF | BAILEY BROS FARM | | | SCAC4 |
| 41 | BYBG | BAGLEY & BAGLEY | | | SCAC4 |
| 42 | BYBH | BYTOWN BACKHAULERS LEASING LTD | | | SCAC4 |
| 43 | BYBK | BAYTANA BAKERY | | | SCAC4 |
| 44 | BYBL | BAY BELL LINES INC | | | SCAC3 |
| 45 | BYBN | BAYOU BARGE LINE INC | | | SCAC3 |
| 46 | BYBN | BYRD, BRIAN K | | | SCAC4 |
| 47 | BYBP | BYB TRANSPORTATION SERVICES INC | | | SCAC3 |
| 48 | BYBR | BOYD BROS INC | | | SCAC3 |
| 49 | BYBT | BUSY B TRANSPORTATION LLC | | | SCAC4 |
| 50 | BYBY | BRYAN & BRYAN TRUCKING LLC | | | SCAC4 |
| 51 | BYC | Northern Airlines Sanya Limited | Callsign: Beiya, | PRC | AVCODES |
| 52 | BYC | Cambodia Bayon Airlines Limited | IATA: BD, Callsign: Bayon Air, IATA Prefix: 688, Commenced operations during December 2014. Ceased operations in 2019. | K | AVCODES |
| 53 | BYC | Northern Airlines Sanya | | | ICAO1 |
| 54 | BYCB | BAY AREA CAB CO | | | SCAC3 |
| 55 | BYCB | BOOTHBAY CRAFT BREWERY | | | SCAC4 |
| 56 | BYCC | BYCAPE TRUCKING CO | | | SCAC3 |
| 57 | BYCC | BROOKS TRUCKING COMPANY INCORPORATE | | | SCAC4 |
| 58 | BYCG | BERRY TRUCKING | | | SCAC4 |
| 59 | BYCH | BEST YET CHARTER | | | SCAC3 |
| 60 | BYCH | BAILEY, CHRISTOPHER | | | SCAC4 |
| 61 | BYCI | BAY CIRCUIT TRUCKING INC | | | SCAC3 |
| 62 | BYCJ | BYCO | | | SCAC4 |
| 63 | BYCL | BUYERS CONSOLIDATORS LTD | | | SCAC3 |
| 64 | BYCM | BAYCREST MOVING & STORAGE | | | SCAC3 |
| 65 | BYCN | BRYCO INC | | | SCAC3 |
| 66 | BYCO | BYRON CONSTRUCTION CO INC | | | SCAC3 |
| 67 | BYCO | B & Y CREATIONS LTD | | | SCAC4 |
| 68 | BYCR | BAY CARRIERS INC | | | SCAC3 |
| 69 | BYCR | BAYCI TRUCKING INC | | | SCAC4 |
| 70 | BYCS | BEYER, CHARLES | | | SCAC4 |
| 71 | BYCT | BAY CITIES TRANSPORTATION CO | | | SCAC3 |
| 72 | BYCT | BAY CITY EXPRESS INC | | | SCAC4 |
| 73 | BYCX | Chelatchie Prairie R.R. Association d/b/a Battle Ground, Yacolt & Chelatchie Prairie R.R. | 7/2005 (not listed) | | NAKINA |
| 74 | BYCX | BATTLE GROUND, YACOLT & CHELATCHIE PRAIRIE RAILROAD (CHELATCHIE PRAIRIE RAILROAD ASSOCIATION) | | | PWRC |
| 75 | BYCX | Battle Ground Yacolt and Chelatchie Prairie Railroad | | | RSRV |
| 76 | BYCX | BATTLE GROUND YACOLT & CHELATCHIE P | | | SCAC4 |
| 77 | BYCY | BAY CITY TRANSPORTATION INC | | | SCAC4 |
| 78 | BYD | Beond-Simdi Operations Private Ltd. | Callsign: Beond, | MV | AVCODES |
| 79 | BYD | MZK Bydgoszcz | City: Bydgoszcz | PL | TRAFFIC |
| 80 | BYDA | BELLYDANCE TOURS INC | | | SCAC4 |
| 81 | BYDA | BYD Auto | | PRC | TRAFFIC |
| 82 | BYDB | BOYD BROS | | | SCAC3 |
| 83 | BYDC | BYNUM, D L & COMPANY INC | | | SCAC4 |
| 84 | BYDD | BYRDS DIESEL SERVICES INC | | | SCAC3 |
| 85 | BYDE | BYINGTON, DALE E | | | SCAC3 |
| 86 | BYDG | BOYD, G R INC | | | SCAC3 |
| 87 | BYDG | BOYD, T S GRAIN | | | SCAC4 |
| 88 | BYDI | BOYD ENTERPRISES INC | | | SCAC3 |
| 89 | BYDI | BIRDIE GOLF CARTS | | | SCAC4 |
| 90 | BYDK | BELYEA, DAVID TRUCKING INC | | | SCAC4 |
| 91 | BYDL | BOYD TANK LINES INC | | | SCAC3 |
| 92 | BYDL | BOYD TANK LINES INC | | | SCAC4 |
| 93 | BYDO | BAITY, DOUG TRUCKING | | | SCAC3 |
| 94 | BYDO | BOYDCO LLC | | | SCAC4 |
| 95 | BYDP | BOYD SPOTTING BUSINESS INC | | | SCAC4 |
| 96 | BYDR | BOYD TRUCKING | | | SCAC3 |
| 97 | BYDR | BOYD TRANSPORTATION SERVICES | | | SCAC4 |
| 98 | BYDS | BOYDS EXPRESS LIMITED | | | SCAC3 |
| 99 | BYDT | BOYD TRUCKING CO | | | SCAC3 |
| 100 | BYDU | GREAT WORLDWIDE LOGISTICS CO. LTD | | CDN | BIC |
