Booking classes matter. aa.com is not reliable in this respect: I checked a fare online LHR-LAS return. aa.com gave me a W booking class seat. After I bought the ticket, it was not W but Q. I care because I usually qualify for EXP on points and not miles. W give 100% points, Q 50%. I called the EXP desk and they told me that for those flights, no W inventory whatsoever. Why show it on aa.com? I ended up changing into a V booking class (addidtional USD 170 but worth it for the points)