Originally Posted by
FlyDeltaJets87
Many fares have advanced purchase requirements, so they are unavailable for purchase within a certain window of the flight, even though those fares are "there".
Yes, but that has nothing to do with
inventory. I frequently see inventory in lower fare buckets that cannot be purchased on the date in question because of advance purchase requirements. (LNK-MSP tomorrow has a flight that's got inventory in all economy buckets, but you can't buy anything lower than B.) Other than a few examples of E being available without some of the higher buckets, I'm yet to see an example of where you have inventory in, say, X but not in H.