Originally Posted by
Absolute
For Flex, for example, the airline could start selling cheap V fares as far as 6 months out... but with a time limit. The V fares could only be valid until they are sold out or 30 days before a flight, at which time that fare will fully disappear. As one fare bucket sells out or expires (e.g. G) then only tickets at the next class up and above can be sold.
The letter doesn't define the advance purchase requirement. There could be different V fares with 3, 7, 14 & 21 day a/p rules.
Revenue management will control how many seats are in each bucket, in addition to what fares are published and what the associated rules are. But the letters in and of themselves don't have meaning other than to define the buckets from which the inventory is sold.
To buy a seat on a flight there must be a published fare, inventory in that fare bucket and you must meet all the rules of the fare.