| Term |
Definition |
| U |
Booking class - use varies depending upon airline |
| UA |
United Airlines |
| UA Metal |
a plane that UA operates. The flight number could still be that of another (Star Alliance) carrier. This has a bearing on earned mileage and other MP benefits. |
| UAE |
United Arab Emirates |
| UAX |
synonym for UX, United Express |
| UC |
United Club |
| UC |
Business class on VS (Upper Class). |
| UC |
Unable to accept, waitlist, cancel and request alternate flight. Passenger is not confirmed and is not waitlisted. |
| UD |
Upper Deck on larger aircraft, like the 744. |
| UDH |
FlyerTalk memberUnofficialDLHelper, who is employed by Delta Air Lines.UnofficialDLHelperanswers questions and offers advice pertaining to Delta Air Lines but isnotofficially a representative of Delta Air Lines in the Delta forum on FlyerTalk. |
| UDU |
Unlimited Domestic Upgrade - for Executive Platinum ("domestic" = USA, Canada, Mexico, Caribbean, Bahamas, Bermuda and Central America) |
| UFC |
Upgrade For Cash |
| UFU |
Unlimited Free Upgrades - See UDU |
| UGS, GS |
United Global Services - Nota bona-fide status level and by invitation only. Likely based on money spent or influence over spending money on UA. |
| UM |
Unaccompanied Minor. A child traveling alone. Special arrangements can be made with most airlines to have the child escorted to the plane and met at the destination(s). If a connection is involved, an agent will meet the UM at the gate and escort him/her to a special room with supervision. |
| UN |
Transaero Airlines |
| UN |
Unable to confirm or waitlist request. Flight not operating. |
| Uncle Leo |
The name adapted by some Delta forum FlyerTalk members for Leo Mullin, former chief executive officer of Delta Air Lines. |
| United.Bomb |
A reference to United Airline's website - generally meant to be uncomplimentary. |
| UPGRADE (UG) |
Transferring to a higher class of service or accommodation, such as from coach to first. Upgrades may be one-class upgrades (see ONE-CLASS) or jump several classes of service. |
| Upgrade Lottery |
The process in which there are more SkyMiles Medallion members at the gate that there are available upgrades on that particular aircraft, which usually results in a selection process as to who is fortunate enough to get upgraded and who is not. |
| US |
Unserviceable / out of service |
| US |
Unable to sell. Have waitlisted. |
| US |
US Airways |
| USPC |
UnitedStatesPreClearance - Facility at some foreign airports (eg. SNN, DUB) to clear US immigration and customs enabling the flight to arrive as a "domestic" flight. |
| UTB |
Un-TicketedBaby aka lap baby |
| UTC |
Universal Coordinated Time (see GMT, Zulu Time) |
| UU |
Unable. Have waitlisted. |
| UUA |
Upgrade Using Avios |
| UX, UAX |
United Express - Commuter flights using smaller RJ, EX or CRJ planes, run by independent contractors, under contract to UA |
