Airline codes| IATA | ICAO | Airline | Call sign | Country | Comments |
|---|
| TUM | UTAir | UTAIR-CARGO | Russian Federation | 2014[1] |
| UEU | United European Airlines | UNITED EUROPEAN | Romania | 2014[1] |
| UCG | Uniworld Air Cargo | UNIWORLD | Panama | 2014[1] |
| CUH | Urumqi Airlines | LOULAN | China | 2014[1] |
| DOD | USAF Air Mobility Operations Control Center | United States |
| DOI | U.S. Department of the Interior | INTERIOR | United States | Office of Aircraft Services |
| CNV | U.S. Navy Reserve Logistic Air Forces | CONVOY | United States | U.S. Navy Reserve Logistic Air Forces, New Orleans, LA, USA |
| EXM | United Kingdom Civil Aviation Authority | EXAM | United Kingdom | CAA Flight Examiners |
| GIH | Union des Transports Africains de Guinee | TRANSPORT AFRICAIN | Guinea |
| GKA | US Army Parachute Team | GOLDEN KNIGHTS | United States |
| U5 | GWY | USA3000 Airlines | GETAWAY | United States |
| B7 | UIA | UNI Air | GLORY | Taiwan |
| UAB | United Arabian Airlines | UNITED ARABIAN | Sudan |
| UA | UAL | United Airlines | UNITED | United States |
| 4H | UBD | United Airways | UNITED BANGLADESH | Bangladesh |
| UAC | United Air Charters | UNITAIR | Zimbabwe |
| UCS | United Carriers Systems | UNITED CARRIERS | United States |
| UEA | United Eagle Airlines | UNITED EAGLE | China |
| U2 | UFS | United Feeder Service | FEEDER EXPRESS | United States | formerly part of United Express |
| CFU | United Kingdom Civil Aviation Authority | MINAIR | United Kingdom | Civil Aviation Authority Flying Unit |
| KRF | United Kingdom Royal VIP Flights | KITTYHAWK | United Kingdom | In Military Aircraft |
| KRH | United Kingdom Royal VIP Flight | SPARROWHAWK | United Kingdom | In Civil Chartered Aircraft |
| SDS | United Kingdom Civil Aviation Authority | STANDARDS | United Kingdom | Training Standards |
| TQF | United Kingdom Royal VIP Flights | RAINBOW | United Kingdom | Helicopter Flights |
| CGX | United States Coast Guard Auxiliary | COASTGUARD AUXAIR | United States |
| AGR | United States Department Of Agriculture | AGRICULTURE | United States |
| UAD | University Air Squadron | United Kingdom | Colerne |
| UAJ | University Air Squadron | United Kingdom | Glasgow |
| UAA | University Air Squadron | United Kingdom | Leuchars |
| UAS | University Air Squadron | United Kingdom | RAF Cranwell |
| HBU | Universal Avia | KHARKIV UNIVERSAL | Ukraine |
| HLE | UK HEMS | HELIMED | United Kingdom |
| U7 | JUS | USA Jet Airlines | JET USA | United States |
| LEA | Unijet | LEADAIR | France |
| MSH | US Marshals Service | MARSHALAIR | United States | US Department of Justice |
| NDU | University of North Dakota | SIOUX | United States |
| PNA | Universal Airlines | PACIFIC NORTHERN | United States |
| Upali Air | UPALI | Sri Lanka | defunct |
|
| RAU | Uganda Royal Airways | UGANDA ROYAL | Uganda |
| SAU | United Aviation Services | UNISERVE | Spain |
| U6 | SVR | Ural Airlines | SVERDLOVSK AIR | Russia |
| TRB | Ukraine Transavia | KIROVTRANS | Ukraine |
| UAF | United Arab Emirates Air Force | UNIFORCE | United Arab Emirates |
| UAI | Union Africaine des Transports | UNAIR | Ivory Coast |
| UCC | Uganda Air Cargo | UGANDA CARGO | Uganda |
| UCH | US Airports Air Charter | US CHARTER | United States |
| UCO | Ucoaviacion | UCOAVIACION | Spain |
| UES | Ues-Avia Aircompany | AVIASYSTEM | Ukraine |
| QU | UGA | Uganda Airlines | UGANDA | Uganda | Ceased operations 2001 |
| UGC | Urgemer Canarias | URGEMER | Spain |
| UHL | Ukrainian Helicopters | UKRAINE COPTERS | Ukraine |
| UHS | Ulyanovsk Higher Civil Aviation School | PILOT AIR | Russia |
| UJR | Universal Jet Rental de Mexico | UNIVERSAL JET | Mexico |
| UJT | Universal Jet Aviation | UNI-JET | United States | Cancelled 2014 - Renamed Journey Aviation with code JNY |
| UKI | UK International Airlines | KHALIQ | United Kingdom |
| UKL | Ukraine Air Alliance | UKRAINE ALLIANCE | Ukraine |
| UF | UKM | UM Airlines | UKRAINE MEDITERRANEE | Ukraine | Ukraine Mediterranean Airlines |
| UKN | Ukraine Air Enterprise | ENTERPRISE UKRAINE | Ukraine |
| UKP | United Kingdom Home Office | POLICE | United Kingdom |
| 6Z | UKS | Ukrainian Cargo Airways | CARGOTRANS | Ukraine |
| ULT | Ultrair | ULTRAIR | United States |
| ULH | Ultimate HELI | ULTIMATEHELI | South Africa | Ultimate HELI (Pty) Ltd |
| ULR | Ultimate Air | VIPER | South Africa | Ultimate Airways (Pty) Ltd |
| UNC | Uni-Fly | UNICOPTER | Denmark |
| UNF | Union Flights | UNION FLIGHTS | United States |
| UNJ | Universal Jet | PROJET | Spain |
| UNS | Unsped Paket Servisi | UNSPED | Turkey |
| UNU | Unifly Servizi Aerei | UNIEURO | Italy |
| UPL | Ukrainian Pilot School | PILOT SCHOOL | Ukraine |
| 5X | UPS | United Parcel Service | UPS | United States |
| URV | Uraiavia | URAI | Russia |
| US | AWE | US Airways | CACTUS | United States |
| USF | USAfrica Airways | AFRICA EXPRESS | United States |
| UH | USH | US Helicopter | US-HELI | United States |
| USJ | US Jet | USJET | United States |
| USX | US Express | AIR EXPRESS | United States |
| UT | UTA | UTair Aviation | UTAIR | Russia | WAS P2 till 2006 |
| UTG | UTAGE | UTAGE | Equatorial Guinea |
| UTR | Utair South Africa | AIRUT | South Africa |
| UTS | Ukrainian State Air Traffic Service Enterprise | AIRRUH | Ukraine |
| UTU | Urartu-Air | Armenia |
| UVA | Universal Airways | UNIVERSAL | United States |
| UVG | Universal Airlines | GUYANA JET | Guyana |
| UVM | Uvavemex | UVAVEMEX | Mexico |
| AIO | United States Air Force | AIR CHIEF | United States | Chief of Staff |
| UVN | United Aviation | UNITED AVIATION | Kuwait |
| HY | UZB | Uzbekistan Airways | UZBEK | Uzbekistan |
| PS | AUI | Ukraine International Airlines | UKRAINE INTERNATIONAL | Ukraine |
| WEC | Universal Airlines | AIRGO | United States |
| US | Unavia Suisse | Switzerland |
| US | USA | US Airways | CACTUS | United States |
| QID | USAF 100th Air Refueling Wing | QUID | United States |
| UIT | University of Tromsø School of Aviation | ARCTIC | Norway |
|
1. ^1 2 3 {{cite web|url=http://www.faa.gov/documentLibrary/media/Order/7340.2E_Basic.pdf|title=FAA Document JO 7340.2E|publisher=}}
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