| 1 | UB | Myanmar Airways | ICAO: UBA, Callsign: Unionair, IATA Prefix: 209, Name changed to Myanmar National Airlines | MYA | AVCODES |
| 2 | UB | Union of Burma Airways | Callsign: Uionair, | MYA | AVCODES |
| 3 | UB | Burma Airways Corporation | Callsign: Uion Air, | MYA | AVCODES |
| 4 | UB | Air Cargo Global s.r.o. | ICAO: CCC, Callsign: Global Cargo, IATA Prefix: 159, IATA Designator changed to CW. | SK | AVCODES |
| 5 | UB | Myanmar National Airlines | ICAO: UBA, Callsign: Unionair, Name changed from Myanmar Airways | MYA | AVCODES |
| 6 | UB | UNION BELT OF DETROIT | | | PWRC |
| 7 | UBA | Myanmar Airways | IATA: UB, Callsign: Unionair, IATA Prefix: 209, Name changed to Myanmar National Airlines | MYA | AVCODES |
| 8 | UBA | Myanmar National Airlines | IATA: UB, Callsign: Unionair, Name changed from Myanmar Airways | MYA | AVCODES |
| 9 | UBA | Myanma Airways | IATA: UB | | ICAO1 |
| 10 | UBAI | URBANO INTERNATIONAL INC | | | SCAC4 |
| 11 | UBB | Usedomer Bäderbahn GmbH | Heringsdorf | D | privat-bahn.de |
| 12 | UBB | Usedomer Bäder-Bahn | | D | TRAFFIC |
| 13 | UBB | Usedomer Bäder-Bahn | | DE | VKM |
| 14 | UBBU | DEN HARTOGH DRY BULK LOGISTICS LTD | | GB | BIC |
| 15 | UBBU | U B C LTD | | | SCAC4 |
| 16 | UBCA | UNITED BULK CARRIERS (USA) | | | SCAC4 |
| 17 | UBCI | UNITED BULK CARRIERS INTERNATIONAL | | | SCAC4 |
| 18 | UBCL | USA BOUQUET COMPANY LLC | | | SCAC4 |
| 19 | UBCM | UNITED BULK CARRIERS INTERNATIONAL | | | SCAC4 |
| 20 | UBCU | UNITED FRUIT CO. | | | PWRC |
| 21 | UBCU | United Fruit | | | RSRV |
| 22 | UBCU | CHIQUITA BRANDS (GREAT WHITE FLEET) | | | SCAC1 |
| 23 | UBCU | UNITED FRUIT CO (CHIQUITA BRANDS IN | | | SCAC4 |
| 24 | UBD | United Airways Bangladesh Ltd | IATA: 4H, Callsign: United Bangladesh, Founded in 2005. Commenced operations on 10 July 2007. Ceased operations on 06 March 2016. | BD | AVCODES |
| 25 | UBD | UR Airlines d/b/a UBD | IATA: UD, Callsign: Urair, All flights operated by Aircompany Jonika LLC. (JNK) | IRQ | AVCODES |
| 26 | UBDI | UB DISTRIBUTORS LLC | | | SCAC4 |
| 27 | UBE | Limited Liability Company Bees Airline | IATA: 7B, Callsign: Flower Bee, IATA Prefix: 517, | UA | AVCODES |
| 28 | UBEI | US BLUE EXPRESS INC | | | SCAC4 |
| 29 | UBEX | United Bio Energy Ingredients, LLC | 7/2005 (not listed) | | NAKINA |
| 30 | UBEX | UNITED BIO ENERGY INGREDIENTS, LLC | | | PWRC |
| 31 | UBFL | UNITED - BUCKINGHAM FRT LINES | | | PWRC |
| 32 | UBFS | URBAN FREIGHT SERVICES | | | SCAC4 |
| 33 | UBG | US-Bangla Airlines Limited | IATA: BS, Callsign: Banglastar, Founded in 2013. Commenced operations on 17 July 2014. | BD | AVCODES |
| 34 | UBKI | UB TRUCKING INC | | | SCAC4 |
| 35 | UBLA | UNIQUE BROKERAGE & LOGISTICS INC | | | SCAC4 |
| 36 | UBLG | USA BORDER LOGISTICS LLC | | | SCAC4 |
| 37 | UBLT | UNIBILT TRANSPORT INC | | | SCAC4 |
| 38 | UBMU | UNITED BALTIC CORP. LTD. | | | PWRC |
| 39 | UBMU | United Baltic Corporation Limited | | | RSRV |
| 40 | UBRG | UTS BROKERAGE | | | SCAC4 |
| 41 | UBRL | UGLAND BROTHERS LIMITED | | | SCAC4 |
| 42 | UBROS | United Brothers | | USA | TRAFFIC |
| 43 | UBRS | UB RESOURCES | | | SCAC4 |
| 44 | UBRV | UNCLE BOBS RV | | | SCAC4 |
| 45 | UBS | Barbedos Aviation Services Limited | Callsign: Barbedos, | WAN | AVCODES |
| 46 | UBSC | US BLUE STAR CO | | | SCAC4 |
| 47 | UBSL | UNIVERSAL BUILDING SOLUTIONS LTD | | | SCAC4 |
| 48 | UBT | Norse Atlantic UK Limited | IATA: Z0, Callsign: Longboat, IATA Prefix: 536, Subsidiary of Norse Atlantic Airways AS. AOC grant 23 September 2022. | GB | AVCODES |
| 49 | UBTA | UGLAND BULK TRANSPORT A/S | | | SCAC4 |
| 50 | UBTE | UTLEY, BRENT TRUCKING | | | SCAC4 |
| 51 | UBTK | US BOND TRUCKING INC | | | SCAC4 |
| 52 | UBTN | URBAN TANKER CORPORATION | | | SCAC4 |
| 53 | UBTO | UNITED BRIDGE TRUCKING CORP | | | SCAC4 |
| 54 | UBTT | UNCLE BEN TRANSPORT INC | | | SCAC4 |
| 55 | UBTX | Union Bag & Paper Corp. | added 7/1955; eliminated 10/1956 | | NAKINA |
| 56 | UBTX | Union Bag-Camp Paper Corp. | added 10/1956; 10/1957-7/1965; eliminated 7/1966 | | NAKINA |
| 57 | UBTX | Union Camp Corp. | added 7/1966; 10/1966-1/1980; eliminated 10/1987 | | NAKINA |
| 58 | UBTX | Union Bag & Paper Corp. | added 7/55 | | NRHS |
| 59 | UBTX | Union Bag-Camp Paper Corp. | 10/57-7/65; eliminated 7/66 | | NRHS |
| 60 | UBTX | Union Camp Corp. | added 7/66; 10/66-1/80; eliminated 10/87 | | NRHS |
| 61 | UBTX | UNION CAMP CORP. [UNION BAG & PAPER CORP.] | | | PWRC |
| 62 | UBTX | Union Camp Corporation | | | RSRV |
| 63 | UBTX | UNION BAY-CAMP PAPER CORP | | | SCAC4 |
