Originally Posted by tristan727
Many thanks, will print and stick on my wall until memorised,so can understand half of what people are talking about here! My only question is -there must be some, albeit minute, difference between k,l,m,n,q ,s,v etc.?
Those are the different fare base "buckets" in Traveller. So availability of cheap fares generally depends on N and V for example (certainly on the Shuttle anyway). They all equate to the same physical seat, just at different price points.
B and H for example are semi-flexible economy (and more important for FT'ers, qualify for Tier Points!).
Sometimes BA will also make different buckets available to different markets (e.g. the UK N bucket might have sold out, whilst the US N bucket hasn't). This is thought to be one reason why aa.com can sometimes throw out much cheaper fares.