Originally Posted by KSinNYC
So how do FT'ers "understand" each other -- are they just very familiar with the airline under discussion?
Yes.
Maybe there could be a mini-glossary with the classes for some of the most frequently used airlines, just so they could all be in one place? Or is there a "reference section" for each airline that I don't know about?
There isn't a reference section for that, although you may find the classes for an airline listed on that airline's website, in their various Customer Support areas.