| 1 | BLK | Westcoast Energy | Callsign: Blue Flame, | CDN | AVCODES |
| 2 | BLK | Chrono Jet, Inc. | Callsign: Blackmat, ICAO designator changed to MBK. ICAO callsign changed to Matblack. | CDN | AVCODES |
| 3 | BLK | USAC Airways 695, LLC | IATA: TD, Callsign: Aero Black, Wholly owned subsidiary of Aero Technologies, Inc. | USA | AVCODES |
| 4 | BLK | Westcoast Energy | | | ICAO1 |
| 5 | BLK | BIG LEVEL & KINZUA RR | | | PWRC |
| 6 | BLKA | BLACK & WHITE TRUCKING CO | | | SCAC3 |
| 7 | BLKB | BLACK TRANSFER | | | SCAC3 |
| 8 | BLKC | BULK CARRIERS INC | | | SCAC4 |
| 9 | BLKD | BLACK DIAMOND SERVICE, INC | | | SCAC3 |
| 10 | BLKD | BLAKELY TRUCKING | | | SCAC4 |
| 11 | BLKE | BLOCKER TRANSPORTATION | | | SCAC3 |
| 12 | BLKE | BXI LLC | | | SCAC4 |
| 13 | BLKF | BULK INC | | | SCAC3 |
| 14 | BLKG | BELLE TRUCKING | | | SCAC4 |
| 15 | BLKH | BLACKHAWK TRANSPORTATION INC | | | SCAC3 |
| 16 | BLKH | BLACKHAWK EXPRESS LTD | | | SCAC4 |
| 17 | BLKI | BLACK TRUCKING COMPANY | | | SCAC3 |
| 18 | BLKI | BLAKE TRANSPORT INC | | | SCAC4 |
| 19 | BLKJ | BULK TRANS | | | SCAC4 |
| 20 | BLKK | BLIEK TRANSPORT INC | | | SCAC3 |
| 21 | BLKL | BLACKLINE AMERICAN CORPORATION | | | SCAC3 |
| 22 | BLKL | BLACKLINE AMERICAN CORPORATION | | | SCAC4 |
| 23 | BLKM | Black Mesa & Lake Powell | 1/1980-7/2005 | | NAKINA |
| 24 | BLKM | Black Mesa & Lake Powell | 1/80-7/2000 | | NRHS |
| 25 | BLKM | BLACK MESA & LAKE POWELL RWY. | | | PWRC |
| 26 | BLKM | Black Mesa and Lake Powell Railway | | | RSRV |
| 27 | BLKN | BLACK NAVIGATION COMPANY | | | SCAC3 |
| 28 | BLKO | BLAKE OIL CO | | | SCAC4 |
| 29 | BLKP | BULK TRANSPORTATION, INC | | | SCAC3 |
| 30 | BLKP | BULK TRANSPORTATION | | | SCAC4 |
| 31 | BLKP | Blackpool Transport Services Limited | City: Blackpool | GB | TRAFFIC |
| 32 | BLKQ | BLENKER OIL CO | | | SCAC3 |
| 33 | BLKQ | BOWMAN, L K CO | | | SCAC4 |
| 34 | BLKR | BLACKDOG TRANSPORT INC | | | SCAC4 |
| 35 | BLKS | BLACKS TRANSFER INC | | | SCAC3 |
| 36 | BLKT | BLACKSHEAR TRANSPORTATION CO, INC | | | SCAC3 |
| 37 | BLKT | BLACKSTONE ENTERPRISE | | | SCAC4 |
| 38 | BLKU | BULKHAUL LTD | | GB | BIC |
| 39 | BLKU | BULK HAUL KIESERLING | | | PWRC |
| 40 | BLKU | Bulkhaul | | | RSRV |
| 41 | BLKU | BULKHAUL CO., LTD | | | SCAC3 |
| 42 | BLKU | BULKHAUL (UK) LTD | | | SCAC4 |
| 43 | BLKV | BLAKELY, H TRANSP SERVICES INC | | | SCAC3 |
| 44 | BLKV | BLACK LAKE VENTURES | | | SCAC4 |
| 45 | BLKW | BLACKHAWK TRANSPORT INC | | | SCAC4 |
| 46 | BLKY | BILKAYS EXPRESS CO | | | SCAC3 |
| 47 | BLKZ | MID-AMERICA INTERMODAL EQUIPMENT CORPORATION | | | PWRC |
| 48 | BLKZ | Mid-American Intermodal Equipment Corporation | | | RSRV |
| 49 | BLKZ | MID-AMERICA INTERMODAL EQUIPMENT CO | | | SCAC4 |
