| Name | Explanation | Examples |
|---|---|---|
| U | Primary trainer, Uchebnyj | U-1, U-2, UPe-2 |
| UAV | Unmanned Aerial Vehicle [English] | |
| UB | Multipurpose machinegun by Berezin, Universal'ny Berezina | UB |
| UBK | Multipurpose machinegun by Berezin, free-firing (wing mounted) modification , Universal'ny Berezina Kryl'evoj | UBK |
| UBS | Multipurpose machinegun by Berezin, synchronized modification , Universal'ny Berezina Synkhronny | UBS |
| UBT | Multipurpose machinegun by Berezin, turret modification , Universal'ny Berezina Turel'nij | UBT |
| UkrVozdukhPut' | Ukrainian Society of Airways , Ukrainski Vosdukhni Put' , Established in 1923 | |
| UMA | Naval Aviation Management , Uprevlenie Morskoj Aviatsii | |
| UPAZ | Aerial refueling gear , U****? P****? AviaZapravka ? | |
| UPB | Transitional trainer-bomber, intended for transition from primary trainer aircraft to the bomber. Also - crew trainer. Uchebno-Perekhodnyj Bombardirovschik, учебно-переходной бомбардировщик УПБ |
See KAI-1 N°3 UPB |
| USR | Special Works Management , Uprevlenie SpetsRabot | See BICh-17 project |
| UT | Basic trainer, Uchebno-Trenirovochny | UT-1, UT-2, UT-3 Pe-2UT |
| UTI | Fighter Trainer, Uchebno-Trenirovochny Istrebitel | UTI-4, UTI-26, La-15UTI |
| UTS | Learning/Training Aircraft , Uchenbno-Trenirivochnyj Samolet (modern) | See M-200 project |
| UVVF | Management of the Military AirFleet, Upravlenie Voenno-Vozdushnogo Flota | |
| UVVS | Upravlenie Voenno-Vozdushnikh Sil, Military Air Force Management | |