VDB = "Voluntarily Denied Boarding" -- when a flight is oversold, they ask for volunteers. If there are more passengers than seats, these volunteers are paid compensation (either in United $$$ vouchers or in the form of a free ticket for later use) and are re-accomodated on another flight.

Operation upgrades occur when a passenger is upgraded without any form of payment or award to a higher class cabin for "operational" reasons. This often happens when the economy class cabin is oversold but the business / first class cabin has still space available.

Since VDB and operational upgrades both tend to happen when the economy cabin is oversold, asking about VDB *before* asking about an operational upgrade seems less pushy than just asking for an upgrade. It also means that you're only likely to ask for an upgrade if there's a reasonable likelihood of one being available. No matter how nicely you ask, if the economy cabin isn't full, you're taking your assigned seat.

On United, at least, "candidates" for operational upgrades are selected by their Mileage Plus status. In lieu of high-status passengers, being appropriately dressed and being friendly goes a long way towards getting selected for the elusive upgrade!


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Please visit The Mileage Runner's Toolkit and Unofficial United Airlines Guide

[This message has been edited by MatthewClement (edited 12-05-2001).]