Showing 1,012 registered airlines with a combined fleet of 8,882 airframes.
| Airline Name | ICAO / IATA | Fleet Size |
|---|---|---|
| United Carriers Systems | UCS | 0 |
| United Feeder Service | UFS / U2 | 0 |
| United Parcel Service | UPS / 5X | 215 |
| United States Air Force | AIO | 86 |
| United States Coast Guard Auxiliary | CGX | 1 |
| United States Navy | CNV | 165 |
| United States Transportation Command | CMB | 0 |
| Universal Airlines | WEC | 0 |
| Universal Airlines | PNA | 0 |
| Universal Airways | UVA | 0 |