hi everybody, i've just got two quick questions about logistics. i've already got my itin set, it is london-delhi-hongkong // beijing - hongkong - bangkok - hong kong(x) - new york - buenos aires - santiago - easter island - santiago(x) - lima - miami(x) - new york - washington - new york - madrid (x) - tel-aviv - london

... the "x" is supposed to mean transfer, right?? ...

anyway, i'm wondering two things. right now, my reservation shows all the flights as being booked under "L" class, which does not give me full mileage on all airlines (I am using AA, BA, Cathay, Iberia and LAN Chile) ... is there a way to change the booking class on the fare?? also, which frequent flyer program should i join. assuming that i'm based in the US, but fly to the UK very often, is the AA or BA program better to join? where will i get more miles? where are miles more valuable?

thanks.
-daniel