Originally Posted by
DiscoPapa
Whenever you see F# Y#, those are the number of seats authorized for purchase. For example, Y6 doesn't mean there are 6 actual seats remaining in coach. It means that we are willing to sell 6 more. Y9 is the highest it goes, so it could mean we are willing to sell 9 more seats or it could be 200 more seats. Also, the coach cabin could already be oversold ("sold above actual capacity"), but you have no way of knowing that.
THIS is the correct answer. If one were to look in the travel agents' handbook it would describe the number (as in Y#) as "the number of seats the airline is willing to sell at that fare class" or "the number of seats available to sell in the fare class" ... as above. That's why the formal name of that information is
availability.
And first class (F, A, et al) availability is almost always completely independent of coach (Y, B, M et al) availability (there are some arcane company-dependent exceptions). So it is indeed possible to have almost any combination of #s (providing #<9).